My mechanic says my suspension is not adjustable. Does that mean the wheels can't be aligned?

No, it simply means the vehicle manufacturer was too cheap to design adjustable suspension components when it engineered your car. When a car maker designs a car, engineers and accountants scrutinize each and every component to figure out how they can reduce manufacturing and assembly costs. If a few cents can be saved by leaving out an adjustable camber bolt, caster shim or whatever, they'll do it. They may have great faith in their own ability to build a vehicle that never needs to be aligned or fixed, but we all know from experience that such notions are untrue. So even though a suspension is nonadjustable and shouldn't require any corrections, that doesn't necessarily make it so. Even brand new vehicles can roll off the assembly line with wheels that don't meet their own alignment criteria.

Fortunately, the aftermarket has come up with ways to correct the "mistakes" of the vehicle manufacturers. If the car maker doesn't include provisions for adjusting the suspension, it creates an opportunity for some aftermarket part's supplier to come up with means of making such adjustments possible. These include offset bushings, shims, wedges and other alignment aids. So even though your suspension may have few if any adjustments for things like camber, caster and rear toe (front toe is adjustable on all cars and trucks), there are probably aftermarket alignment aids that allow at least some limited corrections to be made on nonadjustable suspensions.

How much air should I put in my tires?

It depends on the vehicle application, the size of the tires, how much weight is on the tires, and whether fuel economy is more important to you than a smooth ride.

Listed in the owner's manual or on a decal in the glovebox or door jamb in every vehicle are the recommended inflation pressures from the vehicle manufacturer. For most passenger cars, minivans and minipickups, the recommendations range from 27 to 32 psi. For fullsize pickup trucks and sport utility vehicles, the recommended inflation pressures tend to be about 5 to 8 psi higher to reflect the larger tire sizes and greater weight of these vehicles.

It's important to note that the recommended inflation pressures may differ for the front and rear tires.

The manufacturer's recommendations are not necessarily the optimum inflation pressure for your tires, but are generally the best for all-round driving. Adding a couple of extra pounds of pressure will decrease the rolling resistance of the tires and make a slight improvement in fuel economy -- but it will also make the tires harder which in turn may cause a somewhat rougher or harsher ride.

If you're carrying a lot of extra cargo, car pooling, hauling a lot of stuff in the back of a pickup or towing a trailer, a few extra pounds of pressure would be recommended to offset the added weight. Add the extra pounds to the rear tires.

WARNING: Never exceed the maximum inflation pressure specified on the sidewall of the tire. This number is the maximum pressure the tire is designed to safely handle. Higher pressure increases the risk of tire damage (when hitting a bump) or tire failure.

Why Check?

All tires leak a little air over time, with some losing up to half a pound a month. If you're losing more air than this, you probably have a leak (possibly a rim leak or a porosity leak in an alloy wheel). For this reason, tire pressure should be checked at least once a month -- and certainly before taking a long trip or driving at sustained highway speeds.

Underinflated or overinflated tires can wear unevenly. Underinflation also increases tread wear dramatically.

WARNING: Underinflation may also increase the risk of tire failure or a blowout. When a tire with too little air in it (say 12 to 18 lbs.) is driven at highway speeds, the sidewalls are forced to flex excessively. This builds up a lot of heat in the tire which may cause it to fail.

How To Check

Recommended tire inflation pressures are always for COLD tires, which means you should check the tires in the morning before the vehicle has been driven. Driving heats up the tires and causes the air inside to expand. If you check the tires right after driving, therefore, the readings will be at least several pounds higher than normal.

Internal tire pressure will also vary with the ambient (outside) air temperature. Hot weather raises air pressure inside the tires, while cold weather lowers it. So air may have to be added or vented from the tire to compensate for seasonal variations as well.

Use an accurate tire gauge to check your tires. Don't rely on the built-in gauge on a gas station air hose or compressor (which tend to be very inaccurate). And never rely on your eyeballs alone to "judge" the amount of pressure in your tires. The sidewalls on radial tires typically bulge quite a bit even when the tire is properly inflated. If you keep adding air until the bulge is gone, the tire will be seriously overinflated. Likewise, don't wait until the tire is nearly flat to add air. It's nearly impossible to tell the difference between a tire that has 10 lbs. of air from one that has 20 lbs. of air. Use a gauge to check the tires regularly, and add or vent air as needed to keep the pressure within a couple of pounds of the amount recommended by the vehicle manufacturer.

NOTE: Tire inflation pressure should be more or less equal side-to-side. A difference of more than a couple of pounds may be enough to cause a noticeable steering or brake pull.

Why are almost all tires today radial ply tires?

Because radial ply tires are better than bias ply tires.

The belts are layers of woven reinforcing fiber inside the tire under the tread. The belts give the tire strength, keep the tread from squirming and help resist punctures. The belts may be fiberglass, steel, nylon, rayon or aramid fiber.

In bias ply tires, which were common before radials were invented, the innermost plies crisscross like an "X" as they run from bead to bead (side to side), while the outermost plies run lengthwise around the circumference of the tire. This makes a relatively firm tread, but it also increases rolling resistance. And anything that increases rolling resistance increases fuel consumption.

The innermost plies in radial tires, by comparison, run sideways between the beads. This makes the tire more flexible, which reduces rolling resistance and improves fuel economy. Changing from bias ply to radial ply tires can improve fuel economy 10 to 15%, so that's the main reason why most tires today are radials.

The increased flexibility of radial tires also helps improve traction and cornering. Because the tire is more flexible, it is better able to maintain tread contact when cornering. This also allows lower aspect ratio tires (shorter sidewalls) which provide better handling performance.

What are all-season, asymmetrical and directional tires?

Essentially an all-season tire is a tire with a slightly aggressive tread pattern that provides good year-round wet and dry traction characteristics. It tends to be a bit harsher and louder than ordinary tires, but not as harsh or loud as a snow tire.

Some all-season as well as performance tires have a "directional" tread pattern. Directional tires have a "one-way" tread pattern that are optimized for the direction the tires rotate on the car. They must therefore be mounted on either the left or right side. Little arrows or triangles on the sidewall indicate which way the tire is supposed to turn. The tread blocks and grooves are angled to optimize handling. They also do a good job of channeling water out from under the tire on wet surfaces to reduce hydroplaning and improve wet traction. Directional tires can be rotated front-to-rear but cannot be rotated side-to-side.

Another variation in tread design you'll see is "asymmetrical" tires. Tires with an asymmetrical design mix tread patterns or put more rubber on one side of the tread than the other in an effort to make one tire out of two different tread patterns. Some combine a slick-like smooth tread on half the tire (to improve traction) with a block pattern on the other half (for directional stability).

When I'm driving down the highway, my car wants to pull to one side. How come?

A steady steering pull or "lead" to one side may have any of a number of causes. The most likely cause is wheel misalignment. This may be due to rear wheel toe or axle misalignment, front wheel camber misalignment, too much cross camber or caster alignment (more than a degree of difference side to side), or someone having "aligned" the front wheels without the steering wheel being properly centered beforehand. In any event, it will probably be necessary to have the alignment checked to diagnose and correct the problem -- unless one of the following is causing the pull:

An underinflated front tire on one side. Check tire pressures and make sure they are the same side-to-side (no more than a couple of pounds of difference).

Mismatched tires. Tires of different size, aspect ratio or even tread pattern on one side can create enough of a difference in rolling resistance to cause a pull.

A weak or sagging spring. Measure and compare ride height on both sides of your vehicle (measure at the fender openings). If one side is an inch or more lower than the other side, chances are you have a spring that needs to be shimmed or replaced.

A dragging brake. This can be caused by a frozen or sticking disc brake caliper that doesn't allow the pads to kick back out from the rotor or weak or broken return springs in a drum brake that don't pull the shoes back from the drum. Another possibility here might be a packing brake that isn't fully releasing on one side.

An uneven load. If you, your significant other or a passenger is causing your vehicle to lean to one side, it can cause the steering to lead in that direction. Don't laugh, a few hundred extra pounds can make a big difference in a small vehicle -- especially if the weight isn't evenly distributed side-to-side. If you can't do anything about the extra weight, it is often possible to compensate by having the wheels realigned with a "simulated" load positioned in the vehicle. Of course, then your vehicle may lead in the opposite direction if the extra weight is removed.

Excessive road crown. Roads are usually sloped (crowned) from the center towards the sides for drainage. If you spend a lot of time driving on highly crowned roads and find the constant lead to the outside shoulder annoying, you can have the wheels realigned to compensate for the excessive crown. Adding or subtracting camber from one wheel or the other to create a difference in the cross camber alignment of your front wheels can counteract this kind of problem.

Do my wheels need to be realigned after the struts have been replaced?

On most vehicles they do. Here's why:

MacPherson struts are more than overgrown shock absorbers. They're an integral part of your vehicle's suspension. They replace the upper control arms and ball joints and serve as the steering pivots for the front wheels. When the strut assembly is unbolted and removed from the vehicle, the original alignment of the suspension is lost -- unless the position of the camber bolts and upper strut plate are first marked so they can be reinstalled in exactly the same position as before. But this only works if the same original strut is being put back into the car. If the strut is being replaced because it is leaking, damaged or worn out, the dimensions of the new strut will usually vary enough to cause a change in wheel alignment. So wheel alignment should at least be checked to see if adjustment is necessary (which it usually is).

On some import cars, the struts are "rebuildable." The housing has a removable nut that allows the old guts inside to be dumped out and a new cartridge installed. On these vehicles, it should not be necessary to realign the wheels after rebuilding the strut.

I'm buying a new set of tires. Should I have them balanced?

Yes. Balancing helps to guarantee a smooth ride at highway speeds, and it helps to maximize tire life. An out-of-balance tire can be very annoying because it produces a shake that increases in intensity the faster you go. The up-and-down shaking of the wheel is hard on the suspension, not to mention your nerves, and also increases tread wear. An out-of-balance tire can develop a cupped wear pattern. So do yourself and your tires a favor and have them balanced.

Almost all service facilities and tire stores today use an off-car electronic spin balancer to balance the wheels. The tire and wheel are mounted on the balancer, then spun to find any heavy spots on the wheel. The balancer then indicates where weights (and how much weight) need to be placed to counterbalance the heavy spot.

Off-car spin balancers actually check two kinds of balance, "static" and "dynamic." Static imbalance causes a wheel to shake up and down as it spins, so static balance is achieved when both halves of the tire wheel assembly weigh exactly the same. Dynamic imbalance causes a tire and wheel to shake back and forth or sideways as it spins. Dynamic balance is achieved when the front and back sides of the wheel and tire weigh the same.

How often do I really need to have my wheels aligned?

Once. If the wheels on your vehicle are correctly aligned when the vehicle is manufactured at the factory, they should not change alignment until something in the suspension wears out or is damaged. Alignment doesn't change. The only thing that changes it is wear or damage. Hitting a pot hole or a thousand pot holes won't knock your suspension out of alignment unless you hit something hard enough to actually bend metal. That really doesn't happen very often, so having the wheels aligned periodically is a waste of money.

On the other hand, there are valid reasons for having the alignment checked periodically:

• If your tires are wearing abnormally, alignment should be checked to find out why. Chances are something is amiss and needs to be readjusted or replaced. It only takes a 1/8 inch of toe misalignment to drag the front tires sideways the equivalent of 28 feet for every mile traveled!
• If you're buying a new set of tires and want to maximize tread life, it's a good idea to have the alignment checked as insurance. Even if the factory alignment is within the acceptable range specified by the vehicle manufacturer, there's often room for improvement. Resetting alignment to the "preferred specs" (which means the midrange or optimum specs) will usually extend tire life -- sometimes significantly. Considering the high cost of many performance tires today, assuring maximum tire life with an alignment is money well spent.
• If you're experiencing any kind of steering or handling problem, an alignment check may be necessary for diagnostic purposes. An important aspect of aligning the wheels is performing a preliminary alignment inspection of the suspension and steering linkage. This is necessary to determine if there are any worn, damaged or mislocated parts. It's impossible to realign worn or damaged parts so any such parts must be replaced before the wheels can be realigned.
• Wheel alignment is also required when certain suspension and steering components are replaced. On most cars with MacPherson struts, the front wheels should be realigned if the struts are replaced (NOTE: This is not necessary on certain import vehicles that have replaceable strut cartridges). Alignment is also required if the tie rods, tie rod ends, idler arm, steering links, control arms or control arm bushings, steering knuckle or steering rack have been replaced.
• Another benefit of having the wheels aligned is to assure optimum handling and traction for driving safety. Camber, in particular, is a very important angle with respect to keeping the tire's treads in full contact with the road. Tires that lean in or out ride on the shoulder and reduce traction, cornering ability and tread life. Camber can even affect braking. Uneven camber or caster side to side can make a vehicle lead to the left or the right.

What's the difference between a U-joint and a constant velocity (CV) joint?

A U-joint (the "U" stands for "Universal"), which is also called a "Cardan" joint after the guy who invented it, is a type of flexible coupling typically used on both ends of the driveshafts in rear-wheel and four-wheel drive vehicles. Each U-joint consists of a four-legged center cross with needle bearing cups on the ends of each leg of the cross. The bearing cups on one pair of legs are mounted to the driveshaft. The other pair of cups are held in place by a pair of U-bolts attached to a yoke that mates to either the transmission or differential. The bearing cups allow the joint to swivel and bend as the driveshaft follows the motions of the differential and axle as the suspension bounces up and down.

Most original equipment U-joints on newer vehicles are "sealed" and do not require periodic greasing. But many replacement U-joints as well as the U-joints on older vehicles do have a grease fitting which allows the joint to be lubed periodically.

Cv Joints

A constant velocity (CV) joint does essentially the same thing as a U-joint, only better. There are two basic types: "ball-and groove" CV joints (called "Rzeppa" joints after the guy who invented them), and "tripod" CV joints.

Rzeppa CV joints, which are used as the outer joints on most front-wheel drive cars and minivans, consist of a cup-shaped outer housing, a center race and cage assembly. Machined into the outer housing and center race are six grooves that hold six steel balls. The balls are held in position by windows or slots cut into the cage assembly. The joint is designed so that when it bends, the balls are always positioned at the midway point inside the joint. This eliminates the cyclic variations in speed that a U-joint experiences when it operates at more than a few degrees off-center.

A variation on the Rzeppa CV joint is the "cross-groove" CV joint. It also has six balls between an inner race and outer housing. But this type of joint is designed to move or plunge in and out to compensate for changes in driveshaft length that occur as the suspension moves up and down. This type of joint is used as the inboard CV joint on many European and Japanese front-wheel drive cars.

The tripod style of CV joint consists of a three-legged cross or trunnion with roller bearings on the end of each leg. The trunnion is attached to the driveshaft, and the roller bearings run in machined grooves or channels in an outer "tulip" housing. This type of joint is also designed to plunge in and out, and is used as the inner CV joint on most domestic front-wheel drive vehicles. There are also some Japanese and European front-wheel drive cars that use a tripod-style joint as the outer joint.

All CV joints are enclosed by a rubber or hard plastic boot. The boot keeps grease in and contaminants out. CV joints do not require periodic maintenance or greasing, and are engineered to last 100,000 miles or more.

All front-wheel drive cars and minivans have four CV joints: one inner joint and one outer joint on each of the vehicle's two driveshafts (which are also called "halfshafts"). CV joints are also used on the driveshafts of some rear-wheel and four-wheel drive vehicles, too.

Why do front-wheel drive cars and minivans have CV joints instead of ordinary U-joints?

U-joints are not used with front-wheel drive (FWD) because they produce cyclic vibrations when operated at more than a few degrees off-center. A U-joint will cause a change in speed between the driving and driven shafts whenever the joint operates at an angle. As the operating angle of the joint increases, the speed (velocity) of the driven shaft starts to vary during each revolution. And the greater the operating angle, the greater the variation in speed of the driven shaft.

The driven shaft still turns at the same number of revolutions per minute as the shaft that's driving it, but because of the geometry of the U-joint the speed of the driven shaft alternately increases (accelerates) and decreases (decelerates) four times every revolution -- which causes the vibrations we're talking about.

This isn't a concern in a rear-wheel drive application because the U-joints on the ends of the driveshaft are positioned 180 degrees to one another to cancel out vibrations. What's more, both U-joints always operate at the same angle. But in a front-wheel drive application, the outer joint may have to operate at an angle of up to 45 degrees when the wheels are steered. This is too much of a difference between the inner and outer joints angles for U-joints to handle. So constant velocity (CV) joints are required.

Unlike a U-joint, a CV joint always drives the output shaft at the same speed as the input shaft regardless of the operating angle of the joint. Therefore, it doesn't make any difference if the inner and outer joints operate at different angles.

Joint Geometry

In a U-joint, the four-point center cross attaches at two points on either yoke. When the joint is bent, two of the arms on the center cross travel in one elliptical path while the other two arms follow a different elliptical path. This is what causes the speed variations that result in vibration. It's hard to visualize, but that's what happens.

CV joints handle joint angularity differently. The six balls inside a "Rzeppa" style CV joint are positioned so they always travel in a circular path exactly half way between the joint angle. A circular path keeps velocity constant while an elliptical path causes changes in velocity. So that's the inside scoop on why U-joints won't work in FWD applications.

Why are CV joints so expensive to replace?

There are two reasons why: parts and labor. New CV joints typically cost anywhere from $65 to $150 or more depending on the application. A CV joint has a lot of metal and precision-machined components so manufacturing and tooling costs are high.

NOTE: You can save some money by going with a rebuilt joint, but it's still going to cost $35 to $90 and may not hold up as well as a brand new joint (durability varies greatly depending on the rebuilding procedure used: some joints are overhauled using oversized components to compensate for wear while others are remachined to restore like-new tolerances).

Labor (unless you're replacing the joint yourself) is the other factor that adds to the cost of replacement. CV joints are mounted on the ends of the driveshafts located between the transaxle and wheels in a front-wheel drive car. To replace a joint, the driveshaft must be removed from the car. This, in turn, requires removing the wheel, removing a large hub nut that holds the outer end of the driveshaft in the wheel hub, disconnecting the lower ball joint from the steering knuckle so the end of the driveshaft can be pushed back through the hub, and disconnecting the inner end of the driveshaft from the transaxle.

With the proper tools and a hoist, a skilled mechanic can usually remove a shaft in an hour or less. But most shops charge according to a "flat rate" system based on "average" labor times published in a manual. These times are established by the vehicle manufacturers and/or the flat rate manual publishers. Most good mechanics can easily beat the flat rate times, and earn themselves a commission on the difference. Unfortunately, you still pay the same as if it took them the full amount of time to complete the job. Hey, nobody said life was fair.

My mechanic tells me my front-wheel drive (FWD) car has a bad outer CV joint. He says the shaft has to be replaced. Isn't there a less expensive way t

Time is money in the auto repair business. It's much faster and easier for a mechanic to replace the entire driveshaft assembly with both joints on it than to mess around replacing a CV joint on your old driveshaft. Removing the old CV joint from the shaft, disassembling and inspecting the other CV joint on the shaft to make sure it is still good, reassembling and repacking both joints with grease and installing the boots and clamps is a messy and time-consuming job. So that's why your mechanic is trying to give you the "shaft." He isn't trying to cheat you. He's only trying to save himself some time and effort.

The cost of replacement shafts for most FWD cars today has dropped to the point where a complete shaft assembly with new or remanufactured CV joints costs little more (or in some cases no more!) than a brand new replacement joint. That's why most mechanics have gone to swapping shafts instead of replacing individual CV joints.

When the shaft is changed, your old shaft and joints are exchanged for the replacement shaft. Your old shaft is then returned to a company that specializes in shaft rebuilding. Your old shaft is then rebuilt using new or remanufactured joints. The shaft then goes back into the parts distribution pipeline and is sold to the next person who needs one. That's how the system works. It's recycling in action, and it actually saves consumers a lot of money.

If you're pinching pennies and/or don't plan to keep your car for a long time, you can save some money by asking for a shaft with remanufactured, rather than new, joints. The warranty won't be as good, and the joints may not last as long as brand new ones, but you get what you pay for.

Shafts for import vehicles typically cost about 30% more than those for domestic vehicles because there are more different designs of import shafts and joints (some of which can be very difficult and expensive to obtain).

My front-wheel drive car makes a clicking sound when turning. Is anything wrong?

Yes. A clicking sound when turning is one of the classic symptoms of a worn or damaged "constant velocity" (CV) joint. Your car has four such joints on the two front axles: two inboard joints and two outboard joints. The outboard joints are the ones that make a clicking sound when they go bad.

Inside the joint are six steel balls, positioned in grooves between an inner race and an outer housing. The balls are held in position by a cage that looks something like a wide bracelet with windows or slots cut in it. When the joint is new, the balls fit tightly into the cage windows. But as the joint accumulates miles, the cage windows become worn and allow the balls to rattle around. The grooves in the inner race and outer housing also wear, which further contributes to noise.

When driving straight, a worn CV joint is usually quiet (constant noise would indicate a bad wheel bearing or other problem). But when the wheels are turned to either side, the joint bends causing the balls to click as they slide around in their cage windows and grooves. The noise is usually loudest when backing up with the wheels turned. Repacking the joint with grease won't help because the joint is worn and needs to be replaced.

The "normal" life of a CV joint is usually 100,000 miles or more. But a joint can fail prematurely if the rubber boot that surrounds it is damaged or develops a leak.

Cv Joint Boots

The boot, which is made of rubber or hard plastic, serves two purposes: it keeps the joint's vital supply of special grease inside, and it keeps dirt and water out. After five or six years of service, it's not unusual for the boot to develop age cracks or splits. Boots can also be damaged by road hazards or a careless tow truck operator who uses J-hooks to tow your vehicle.

Once the boot seal is broken, the inside grease quickly leaks out. Starved for lubrication, the CV joint soon fails. Dirt and water can also enter the boot and contaminate any grease that's left inside. Either way, a damaged boot is bad news for the joint.

CV joint boots should be inspected periodically (when the oil is changed is a good time) to make sure they are not cracked or torn, and that the clamps are tight. If you see grease on the outside of the boot, it is leaking and needs to be replaced (the sooner the better). If a clamp is loose and the boot is leaking grease at one end, the clamp needs to be replaced.

Original equipment boots are a one-piece design, which means the driveshaft and CV joint have to be removed from the vehicle and disassembled to replace a bad boot. However, there are aftermarket "split-boots" designed for easy do-it-yourself installation. The split-boots eliminate the need to remove and disassemble the joint and driveshaft. You simply cut off the old boot, clean out as much of the old grease as possible from the joint, pack the joint with fresh high temperature CV joint grease (never ordinary chassis grease), then install the new boot. Most split-boots have a seam that is glued together. The seam must not have any grease smeared on it and the glue must be applied carefully for a good seal. Also, the vehicle must not be driven until the glue has cured (about an hour or so).

NOTE: Most professional mechanics do not use split-boots because (1) they don't think a split-boot is as reliable or as long-lived as a one-piece original equipment style boot, and (2) they don't like the idea of installing a new boot on a questionable joint.

By the time a damaged or leaky boot is noticed, the joint has usually lost most of its grease and/or been contaminated by dirt. Unless the joint is removed, disassembled, cleaned and inspected, there's no way to know if it is still in good enough condition to remain in service. If it's making noise, replacing the boot would be a waste of time because the joint is bad and needs to be replaced (most new joints come with a new boot, clamps and grease). But even if the joint isn't making any noise, it may still have wear or internal damage that will soon cause it to fail.

WARNING: A CV joint failure can cause loss of steering control under certain circumstances. If the joint locks up, it can prevent the wheels from being turned.

Can I get into trouble if I disconnect any of the emission controls on my engine?

Yes, if you get caught. No, if you don't. But if you live in an area that requires periodic emissions testing, you probably won't get past an emissions check with missing or disconnected emission controls.

WARNING: Federal law makes it illegal for ANYONE to tamper with, disconnect, remove or otherwise render inoperative ANY emissions-related control device. The Environmental Protection Agency and most states have actually been rather lax about enforcing this rule on motorists, but they haven't hesitated to nail professional service facilities that have been guilty of tampering. Even so, the fines can be hefty. A violation may make you liable for up to a $2,500 fine!

No Tampering

The federal anti-tampering law does not, however, apply to race cars that are not operated on the street, other full-time off-road vehicles, show cars that are not street driven, or vehicles not factory equipped with emission controls (most 1967 and earlier vehicles). So that exempts all antique cars, and most classic cars and muscle cars.

Revisions to the Clean Air Act in 1990 further broadened the definition of emissions tampering to include virtually ANY type of engine or exhaust system modification that alters what comes out the tailpipe. That means any nonstock aftermarket part that is installed on your engine must be EPA-approved and emissions legal (except on the exempt vehicles previously noted).

Before the law was revised in 1990, it was only illegal for professional mechanics to remove or disconnect emission control devices. There was nothing to prevent a motorist from tampering with their own vehicles. That loophole has since been plugged.

What Is Emissions-legal?

Any of the following may be considered emissions tampering and get you into trouble:

• Removing the EGR valve or plugging its vacuum lines
• Removing or disconnecting the PCV valve
• Removing the stock air cleaner and heat riser duct plumbing
• Removing the catalytic converter
• Removing or disconnecting the air pump
• Removing or modifying the stock distributor vacuum advance/retard
• Altering the stock ignition advance mechanism or timing curve
• Replacing the stock distributor with an aftermarket unit that is not emissions certified
• Modifying, removing or replacing the stock computer or PROM chip with a non-certified component
• Blocking the heat riser duct under the intake manifold
• Knocking out the filler restrictor on the fuel tank inlet pipe
• Replacing the stock non-vented gas cap with a vented cap
• Removing or disconnecting the fuel vapor recovery canister
• Changing the idle mixture or stock carburetor jetting
• Removing or modifying the carburetor choke
• Modifying or replacing the carburetor accelerator pump with non-certified components
• Installing an intake manifold or racing manifold that lacks provisions for the stock EGR valve and/or a heat riser duct
• Installing a carburetor that lacks the stock emission hookups
• Installing non-certified fuel injectors
• Installing a long duration "racing" cam that is not emissions-certified
• Installing exhaust headers that lack provisions for a heat riser valve, an air cleaner preheat stove or fittings for an oxygen sensor (if required)
• Installing valve covers with open breathers or no fittings for a PCV valve
• Installing any induction, fuel or ignition system component that is NOT emissions legal

Aftermarket parts manufacturers who make nonstock performance parts for engines, the fuel, ignition or exhaust systems must apply for special certification for any parts they want to sell as being emissions-legal. The California Air Resources Board (CARB) has been the leading government body in this respect, so most submit their proposals to CARB.

First, they must submit detailed proof in the form of laboratory dyno test that document their part does not have an adverse effect on exhaust emissions. These tests are very expensive and must conform with specified test procedures. CARB then reviews the data and may or may not ask for additional information and/or testing. If the product meets CARB's criteria, CARB issues an "executive order" (EO) number (also called an "exemption" number) certifying that the part is in compliance with the applicable clean air rules.

An EO number means the component can be legally manufactured, distributed, sold and installed on a street driven vehicle in the state of California. It also means the component is legally acceptable in all 50 states because the federal Environmental Protection Agency also recognizes the CARB exemption program as meeting their "Memorandum 1A" requirements for certifying emissions legal parts.

Buying Emissions-legal Parts

Virtually all stock replacement parts are emissions-legal regardless of who makes them. But if you're buying any nonstock performance parts, heed the following to make sure you're "safe" from an emissions standpoint:

* Look for wording on the box that says the product is emissions legal or emissions certified for street use in compliance with the EPA and/or CARB rules.

* Look for the EO (executive order) exemption number issued by the California Air Resources Board on the box, product or in the catalog. Remember, the product must have an EO number to be street legal.

* If there is no EO number and one is required to be street-legal, it cannot be legally installed on a street-driven vehicle. Period.

I see blue smoke in my exhaust when I start my engine. Is this anything I should worry about?

Yes, because your engine is burning oil. That, in turn, means your engine has worn valve guides, piston rings An engine that burns a lot of oil (more than a quart in 500 miles) is an engine that needs to be overhauled. Normal oil consumption should be a quart or less in 1500 miles. Most newer engines consume less than half a quart of oil between oil changes (every 3000 miles). So if your engine is burning oil, it's essentially worn out and needs to be repaired.

Because the cost of overhauling or replacing an engine often exceeds the value of an older car or truck, many people will just keep on driving a "mosquito fogger" in spite of the blue clouds of smoke it leaves behind. Never mind the pollution it causes, oil is cheaper than a new or rebuilt engine they reason. That philosophy may be okay if you live out in the sticks somewhere. But in urban areas that require periodic vehicle emissions testing, an engine that's burning oil usually won't pass the test because of excessive hydrocarbon (HC) emissions. You may get by on a waiver after you've spent some money (in vain) on a tune-up, but the fact remains you're still a polluter.

An engine that burns a lot of oil will also eventually foul the spark plugs. Thick, black oily deposits build up on the plugs until they cease to fire. Then the engine misfires and loses power. Cleaning or changing the plugs may temporarily solve the problem, but sooner or later they'll foul out again.

Forget about "miracle" oil additives or pills that claim to stop oil burning. They don't. Better to save your money and put it towards a valve job and new set of rings.

What kinds of emissions should I be concerned about?

All emissions if you're serious about clean air -- or at least worried you won't pass an emissions test. Most emission testing programs to date only check for only two pollutants: carbon monoxide (CO) and hydrocarbons (HC). In areas that have the new "enhanced" I/M 240 emissions testing program, they also check for oxides of nitrogen (NOX) and the operation of your "evaporative emissions" control system (the system that captures and holds vapors from your fuel tank).

Carbon Monoxide (co)

Of the three main pollutants, carbon monoxide is the deadliest because you can't see it or smell it. A concentration of only half a percent (0.5%) CO in the air can render a person unconscious -- and kill within 10 to 15 minutes! Even concentrations as small as four hundredths of a percent (0.04%) can cause headaches and be life threatening after several hours exposure.

WARNING: Never run an engine inside an enclosed garage, not even for a few minutes. The fumes can build up quickly and overcome you before you realize what's happening. Carbon monoxide is invisible and odorless so you can't really tell when it's around.

Carbon monoxide is formed when the fuel mixture is rich and there is insufficient oxygen to completely burn all the fuel. The richer the fuel mixture, the greater the quantity of CO produced. So high CO emissions indicate incomplete combustion typically caused by carburetor maladjustment, a clogged air filter, sticking choke, defective heated air intake system, plugged PCV valve, faulty oxygen sensor, excessive fuel pressure or a fuel injection metering problem.

Carbon monoxide production is highest when the engine is first started because the fuel mixture is richer than normal during this time and the catalytic converter has not yet reached operating temperature.

Carbon monoxide emissions are minimized by maintaining a balanced to slightly lean fuel mixture. This requires careful adjustment of the carburetor idle mixture screws (which may have "limiter caps" to limit the amount of adjustment or are covered with plugs to prevent tampering). On some fuel injected engines, there is also an adjustment for the idle mixture (but it is usually factory sealed to prevent tampering). The fuel mixture is further balanced by the oxygen sensor and computer system. Most of the carbon monoxide that is produced by the engine is converted into carbon dioxide (CO2) by the catalytic converter.

Hydrocarbons (hc)

Hydrocarbon emissions are unburned gasoline and oil vapors. Though not directly harmful, they are a major contributor to smog and ozone pollution (which are toxic). Hydrocarbons in the atmosphere react with sunlight and break down to form other chemical compounds that irritate the eyes, nasal passages, throat and lungs.

HC emissions, which are usually measured in parts per million (PPM), can go up as a result of ignition misfiring (a fouled plug or bad plug wire), "lean" misfiring (incorrect carburetor idle adjustment or vacuum leaks that creates a lean mixture that misfires), loss of compression (such as a burned or leaky exhaust valve), or engine wear that causes the engine to burn oil (worn valve guides, rings and/or cylinders).

Hydrocarbon emissions are controlled by maintaining the fuel mixture so it is neither too lean nor too rich to ignite, by keeping the combustion chamber tightly sealed (good rings and valves), and by maintaining the ignition system (changing the plugs periodically). HC that is produced in the engine is reburned in the catalytic converter and changed into water vapor and carbon dioxide.

Oxides Of Nitrogen (nox)

Nitrogen makes up about 78% of the air we breathe. Though normally inert and not directly involved in the combustion process, combustion temperatures above 2500 degrees F cause nitrogen and oxygen to combine and form various compounds called "oxides of nitrogen," which is abbreviated NOX. This mostly occurs when the engine is under load and the throttle is open wide.

NOX is a nasty pollutant both directly and indirectly. In concentrations as small as a few parts per million, it can cause eye, nose and lung irritations, headaches and irritability. Higher concentrations can cause bronchitis and aggravate other lung disorders. Once in the atmosphere, it reacts with oxygen to form ozone (which is also toxic to breathe) and smog.

To reduce the formation of NOX, Exhaust Gas Recirculation (EGR) is used. By recirculating a small amount of exhaust gas back into the intake manifold to dilute the air/fuel mixture, EGR has a "cooling" effect on combustion, thus keeping temperatures below the NOX formation threshold.

On 1981 and later engines with computerized engine controls, a special "three-way" catalytic converter is used to reduce NOX in the exhaust. The first chamber of the converter contains a special "reduction" catalyst that breaks NOX down into oxygen and nitrogen. The second chamber contains the "oxidation" catalyst that reburns CO and HC.

High NOX emissions are almost always due to a defective EGR valve (or some component that controls the operation of the EGR valve). A related symptom that usually occurs when EGR is lost is spark knock (detonation) during acceleration.

Evaporative Emissions

The fuel vapors that evaporate from your fuel tank can be another source of smog and ozone pollution. So fuel systems for the past twenty years have been sealed to prevent the loss of vapors.

Some venting of the tank must be provided so it can "breathe" during temperature changes and when the engine is running, so this is provided by hoses connected to a charcoal filled canister usually located in the engine compartment. The charcoal particles in the canister soak up and store fuel vapors when the engine is not running. Then, when the engine is started, a "purge valve" opens to siphon the vapors into the engine where they are burned.

If the canister or any of its hose connections leak (or the gas cap does not seal tightly), fuel vapors can escape into the atmosphere around the clock. The amount of pollution can really add up, especially during hot weather, so it's important to make sure the system is functioning properly. The new OBD II test program includes a pressure check of the fuel tank system as well as a flow test of the purge valve.

My car failed an emissions test. Now what?

You try to figure out why it failed the test, get the problem fixed and then try to pass the test again. This may or may not be an ordeal depending on what's wrong with your engine, how easily the problem is to diagnose and repair, and whether or not you flunk a retest.

The worst case scenario is spending a lot of money on repairs only to find that they didn't solve your emissions problem. You bounce back and forth between the repair facility and test station, wasting time and money all the while cursing the incompetent mechanics who tried to fix your car and the bureaucrats who created the clean air emissions testing program.

But in states or municipalities where periodic emissions testing is required, you cannot get your vehicle registration or emissions compliance sticker unless you either pass the test or meet the "waiver" requirements.

A "waiver" is a kind of loophole that allows some vehicles to get past an emissions test even when they can't meet the applicable emission requirements. Some would argue this isn't fair to those whose vehicles meet the requirements and pass the test, but nobody said emissions testing was fair.

Waivers were created by politicians who recognized the fact that many people (voters) can't afford to pay for all the repairs that might be required to pass an emissions test. So credit is given for a good faith effort and for spending a fixed dollar amount on repairs. Once you've spent up to the limit, you get an automatic pass.

Waiver limits vary from one state to another, and some vary by the model year of vehicle. Waiver limits typically range from $75 up to $150, but may be as much as $450 on new vehicles in some states). So if you don't know what the applicable waiver limit is on your vehicle, ask. Unless you're a real zealot about clean air, there's no legal reason to spend a dime more than the waiver limit on emission repairs.

How To Improve Your Odds Of Passing An Emissions Test

The best way to improve the odds of passing an emissions test is to maintain your vehicle. A well-maintained engine is usually a clean engine as far as emissions are concerned.

Changing the spark plugs, air filter, fuel filter, PCV valve and oil regularly (or just before an emissions test), checking ignition timing and adjusting the carburetor (if you have an older vehicle) can reduce emissions and greatly improve your chance of passing.

Also, filling up your fuel tank with gasoline that contains 10% ethanol alcohol (many premium grade fuels use alcohol as an octane booster) may help lower your emissions even more. Many areas now have "reformulated" gasoline that contains alcohol or MBTE that adds oxygen to the fuel to reduce carbon monoxide and hydrocarbon emissions.

Just before the test, make sure your vehicle is at normal operating temperature. Take it out for a short spin down the expressway. This will heat up the oxygen sensor and catalytic converter to minimize emissions.

How can I find a competent mechanic to fix my car.

For starters, ask around. Ask your friends and people at work where they get their vehicles serviced. If they're happy with a certain repair facility or technician, then give that repair facility or technician a try. If they do good work and your satisfied with the results, then you've solved your problem.

If you don't get any specific recommendations or are reluctant to ask others for their advice, you can always look for the "ASE" logo. The National Institute for Automotive Service Excellence conducts competency tests in many different areas of auto repair. To become certified in a repair specialty, a technicians must pass a tough written examination as well as meet minimum experience requirements. What's more, the technician must recertify every 5 years to keep his credentials. Those who pass the exams receive a wall certificate listing their areas of expertise, and and ASE emblem that can be worn on their uniform. Technicians who pass all eight ASE automotive tests become certified "Master Technicians."

Having a technician who is ASE certified work on your vehicle is no guarantee he won't foul up or try to cheat you. But your chances are probably better with an ASE certified technician than someone who doesn't take their profession seriously. Most ASE technicians see themselves as professionals and strive to do their best.

How should I handle a dispute if I'm not satisfied with a repair?

If you believe you've been ripped off, first try to resolve the problem with the service manager. If you were charged for something you didn't request, authorize or understand, try to get an explanation. Perhaps it was just a misunderstanding.

If you can't reach a satisfactory agreement, then try the following:

* Move up the ladder to the next level of management. If you're problem is with a new car dealer, then contact the auto manufacturer's regional office or their customer satisfaction department. If your problem is with a chain store of some type, contact the regional or national office. If you're dealing with an independently owned business, speak directly to the owner.

* If the problem or disagreement can't be resolved (or you believe you've been cheated), register a complaint with your local Better Business Bureau. The BBB has no enforcement authority, but they can sometimes bring pressure to bear on a member that may lead to a resolution.

* Contact your city or state consumer affair office. They will often take a very aggressive approach on your behalf to settling the problem, especially if they've had other complaints on the same business.

* If repair facilities must be licensed in your area, contact the agency that regulates auto repair businesses. (In California, this would the the Bureau of Auto Repair.)

* If you suspect outright fraud, contact your state attorney generals office (or the applicable government agency that polices auto repair fraud cases). They may consider running an undercover sting operation against the facility if they have reason to believe you're not the only one who has been cheated.

* If you're a real crusader, you might even contact a local television news station and encourage someone to "look into" the matter. A news crew at the front door is sweet revenge.

* Certainly tell all your friends and anyone who will listen what a bad experience you had with this particular service facility. It won't do you any good but it may help others steer clear of trouble.

* Consider legal alternatives. You can always refuse to pay and fight it out in court. But legal action is always expensive and time-consuming whether you win or lose.

What is the "Motorist Assurance Program" (MAP)?

It is a nonprofit association that was formed to address consumer and industry concerns about auto repair issues. MAP promotes voluntary "uniform inspection guidelines" as well as a "code of ethics" as a means of improving service and the industry's image to the public.

The MAP organization evolved as a response to allegations that the auto repair industry was ripping people off and selling a lot of parts and services that were not necessary. The issue came to a head in 1992 when a large automotive retail chain store ran afoul of the authorities in California for allegedly overselling unnecessary brake work and other repairs. The investigation snowballed and soon the retailer was facing possible legal action in a number of states all across the country. Congress even got into the act by holding a series of hearings to look into the issue of auto repair fraud, and specifically the practice of "incentive compensation" (paying a commission) to employees for selling parts and services. There was even talk of outlawing the system of commission pay altogether for any type of automotive parts or service work!

The auto retailer in question along with much of the rest of the auto repair industry was running scared, and rightly so. The last thing anybody wanted was more government rules and regulations, especially ones that would likely be ill-conceived and poorly written by people who knew nothing about auto repair. So under the umbrella of the Automotive Parts and Accessories Association, the original MAP organization was formed.

MAP originally stood for "Maintenance Awareness Program." The coalition of members included many of the domestic and import vehicle manufacturers, retail chain store parts and service providers, parts manufacturers and others. The group's original goals were to (1) take the heat off the auto repair industry by directly addressing consumer concerns over repair abuse, (2) to develop a code of ethics for the auto repair industry, (3) to do something about the repair industry's tarnished public image, and (4) to develop standardized or "uniform inspection guidelines" designed to protect consumers against repair abuse and to also help technicians do a better job of servicing their customer's vehicles.

After months of committee meetings and wrangling, MAP met its objectives. The group succeeded in establishing an open dialogue with various governmental agencies. No new laws were passed that would pose additional regulatory burdens on the auto repair industry, and voluntary standards were adopted that addressed the issues of concern to consumers, namely a series of uniform inspection guidelines for various areas of the vehicle (see related question 132 for a list).

It's important to note that the guidelines were a monumental undertaking since no such standards had ever before been developed. Everyone had operated on the principle of "industry accepted practices" which varied widely. There were many disagreements over both minor and major points in the guidelines that had to be hammered out to everyone's satisfaction. Most of that work has been accomplished. But MAP says it is an ongoing process and will continue to be subject to review and possible change.

Another change that came about was that many automotive service retailers eliminated or revamped their employee incentive pay programs to reduce the chance for abuse. Most have also agreed to adhere to the code of ethics and to implement the uniform inspection guidelines to provide better service and customer satisfaction.

For additional information about MAP, or to obtain copies of the uniform inspection guidelines, contact:

Map

808 17th Street NW, Suite 200

Washington, D.C. 20006

Phone: 202-466-7050

I want to minimize the risk of my vehicle being stolen or broken into. What should I do?

Keep it inside a locked garage with an armed guard and Doberman on duty! Or, drive a car that nobody would want to steal.

Seriously, there are some common sense precautions you can use to minimize the risk of your vehicle being stolen or broken into:

Never leave the keys in the ignition, and never leave the engine running while you run into a store or drop something off. You car might not be there when you come back, and you might even be issued a ticket for such stupidity!

Always lock your car, even when running short errands to the grocery store or leaving your car in your own driveway. A car thief will walk right up to an unlocked car in broad daylight, hop in and be gone in 30 seconds. Locking the doors won't prevent him from breaking into or stealing your car, but it will slow him down and may discourage him enough to pick on someone else's car.

Never leave valuables (purses, briefcases, radar detectors, money, portable electronic devices, leather coats, etc.) in plain view. They encourage thieves to break in and help themselves. Either take the valuables with you or lock them out-of-sight in the luggage compartment.

Avoid parking where you have to leave your keys with a valet or parking attendant. It's a simple matter to make a duplicate key and steal your car later. Use self-park facilities where possible.

Park in well-lighted areas, preferably where there are people and/or traffic nearby. This discourages casual thieves from breaking and entering.

If you're installing an expensive stereo system in your vehicle, think hard about getting a "pull-out" unit that can be removed for safe-keeping if you have to park the vehicle outside. Or at least buy a radio that has a theft-deterrent code that makes it inoperable if somebody rips it out of your dash.

Install an aftermarket alarm system on your vehicle. There are many different types from which to choose. A loud, annoying alarm may draw attention, but doesn't necessary deter theft (more often than not, it will draw unwanted attention when it goes off accidentally and annoys your neighbors). A good alarm system should trigger if someone breaks into the car (senses the door opening and/or the sound of breaking glass), opens the hood or trunk, or attempts to tow the vehicle (motion sensor). What's more, the system should disable the ignition so the would-be thief can't start the engine once he gets inside your vehicle.

Install a tracking system. This may not prevent a thief from stealing your vehicle, but it will help the police track him down, catch him and hopefully recover your vehicle intact. LoJack is one such system. If your vehicle is stolen, a radio transmitter that is hidden inside the vehicle will be activated and will signal the police. The police send out a signal that activates the transmitter so they can pinpoint your vehicle's location. International Teletrac is a similar system but activates if the vehicle is started without a key.

Install a steel locking collar around your steering column to discourage thieves from "hot wiring" your ignition. A common means to stealing cars (particular GM cars) is to simply break into the plastic steering column with a screwdriver, pop out and bypass the ignition switch. The steel collar, which generally sells for less than $50, makes this much harder and usually discourages most would-be car thieves.

Install a locking device (club or bar) on the steering wheel. These are inexpensive and discourage thieves by making it difficult to steer the vehicle. Thieves often get around such devices by sawing or cutting through the steering wheel. But a number of companies are now selling steel shields that install under the bar or club to make this more difficult. A shield will also protect the driver side air bag against theft (a hot-theft item these days because they're worth several hundred dollars apiece!)

One of the best ways to discourage professional car thieves (but not teenagers who want to steal your car for a joy ride) is to have all your vehicle's major components (including glass) marked with your vehicle's VIN number. Chop shops make their living by removing valuable parts and selling them to body repair shops. But it's much harder for them to do this if the parts have VIN numbers. They'd just as soon avoid your vehicle and steal somebody else's.

When driving in your car, you can minimize the risk of a "car jacking" by keeping your doors locked, paying attention to what's going on around you when stopping at an intersection and being ready to drive away should a stranger approach your vehicle.

Some companies have also developed "carjacking" alarm systems that will disable the ignition after several minutes if the door is opened while the engine is running. Other systems reportedly fill the vehicle with smoke or shock the carjacker with a non-lethal jolt of electricity when he attempts to drive away with your vehicle.

Are there general safety tips I should follow when working on my own car?

First and foremost, do not attempt repairs that are beyond your ability. If you feel unsure about a repair, you should seek out a competent professional to do the work for you. Better to pay someone who knows what they're doing than to attempt to fix it yourself and screw it up. Many systems on vehicles today are very complex. Repairs often require considerable skill and expertise, not to mention special tools and equipment. A simple mistake could ruin sensitive (and expensive!) electronic components. So don't tackle jobs that are beyond your abilities.

Know your physical limits, too. Don't attempt repairs yourself if you're not physically able to do the work. Replacing certain components may require heavy lifting (changing or removing tires, pulling a cylinder head, etc.), crawling under the vehicle, laying or working in an awkward position, reaching, bending, twisting, pulling, tugging, straining, jerking and motions you may not be accustomed to making. Use common sense. If you have a bad back, joint problems or lack the physical strength to do something, then don't. Hire someone to do it for you.

Also, do not attempt to undertake any maintenance or repair work on your vehicle if you're tired, not feeling well, tipsy, on medication or otherwise impaired. Exhaustion, illness, alcoholic beverages and even some medications may affect your judgment and perception creating a potential for injury or error.

Don't smoke when working on any fuel related components (fuel filter, carburetor, fuel injectors, fuel pump, fuel tank or fuel lines). Better yet, don't smoke at all. It's bad for your health!

Have a fire extinguisher nearby just in case. The fire extinguisher should have a "B" (liquids & grease fires) and "C" (electrical fires) rating.

Don't smoke or get any sparks near the battery. Batteries contain hydrogen gas which is very explosive.

Never crawl under an improperly supported vehicle. In other words, don't trust a jack alone to hold the vehicle up.

Always use a pair of support stands positioned underneath the vehicle to keep it from falling on you. Make sure the support stands are of sufficient strength to hold up the vehicle's weight, too. Don't use blocks of wood, boxes, wheels or bricks for supports because these may slip or collapse and allow the vehicle to fall.

Always disconnect one of the battery cables when doing electrical repair work (as when replacing a starter, installing a radio, fixing a broken switch or wiring, etc.). This will prevent accidental shorts that could damage the wiring or start a fire. This is also a very important precaution to heed when working under the dash of any vehicle equipped with an air bag. Crossing the wrong wires might set off the air bag (which could cause injury and is very expensive to replace).

Never disconnect or unplug any electrical connector while the engine is running or the key is in the "on" position (unless specifically instructed to do so as part of a diagnostic procedure in a shop manual). Unplugging connectors while current is flowing through them creates a voltage spike that can damage sensitive and expensive electronic components.

Do not wear loose clothing, jewelry, rings, neckties, scarves or bulky gloves when working on your vehicle. If you have long hair, tie it back or cover it. These items may become entangled in pulleys or moving parts causing serious injury, dismemberment or death!

Watch out for the drive belts, pulleys, fan and other moving parts when working under the hood if the engine is running.

Watch out for hot stuff, too. If the engine is running or the vehicle has been driven within the past half hour or so, the engine, radiator, exhaust manifolds, catalytic converter, muffler and pipes will be hot.

Never open the radiator cap on a hot engine. Always allow the engine to cool for at least an hour before attempting to open the cap. Even then, use extreme caution. Place a rag over the cap, then loosen it slowly to the first detent or stop. At this point any residual pressure and steam should be released. Wait until all pressure has escaped before removing the cap the rest of the way.

Avoid electrical shocks when working around the ignition system. The normal battery voltage in passenger car and light truck electrical systems is only 12 volts and will not harm you. But the ignition system bumps the primary voltage up to 25,000 to 40,000 volts which can give you a nasty shock if you touch a spark plug wire, the ignition coil or distributor cap while the engine is running.

Wear eye protection when working under the vehicle (to keep dirt and debris from falling into your eyes), when pounding or grinding on anything (to keep metal chips out of your eyes), when jump starting the battery (to keep acid out of your eyes should the battery explode), when working on air conditioning components (to keep refrigerant out of your eyes), and/or when doing anything that might pose a risk to your sight.

Do not open up any brake lines or replace any components in a vehicle equipped with an "integral" ABS system (one where the master cylinder is combined with the ABS modulator, pump and pressure accumulator) without first depressurizing the system. This can usually be done by depressing the brake pedal 24 to 40 times while the key is off.

Use caution when opening any fuel lines on a fuel injected vehicle. The pressure in some systems may be as high as 80 to 90 psi when the engine is running. So do not open any fuel line while the engine is running unless your fire insurance and life insurance are both paid up. Residual fuel pressure can remain in the lines for many hours after the engine has been shut off. To minimize fuel spray, wrap a rag around the hose or line before loosening it, or relieve pressure in the line using a procedure approved by the vehicle manufacturer (refer to a shop manual for details).

Minimize distractions while working on your vehicle. This includes small children, pets, friends, spouses, in-laws or others who may distract you from your work. This will go a long ways towards reducing the risk of injury and making a mistake.

Tell someone if you're going to be working on your vehicle outdoors or if you're going to be working underneath your vehicle. Hopefully, they'll know how to dial 911 should the need arise.

If you're working outdoors and using power tools, make sure the extension cord you're using is rated for outdoor use, that the extension cord and tools are properly grounded (a "ground fault interrupt" outlet is recommended), and that the cord has the proper amp rating for the tools you're using.

My engine quit running and won't start. It cranks normally, but just won't go. What's wrong?

You may have an ignition, fuel delivery or compression problem.

1. Check for spark first. If there's no spark, you may have a failed ignition module, ignition pickup, ignition coil or open in the ignition circuit (bad ignition switch or neutral safety switch).

2. If you have spark, check for fuel. On carbureted engines, remove the air cleaner, hold the choke open, look down the carburetor throat and work the throttle linkage. If you don't see any fuel squirting into the carburetor, the problem may be a stuck needle inlet valve in the carburetor, a bad fuel pump, a plugged fuel filter, a plugged or frozen fuel line, an obstructed fuel tank pickup screen, or no fuel (or water contaminated fuel) in your tank.

3. If you have spark and fuel, your timing chain or belt may have broken or slipped. If your engine has a distributor, remove the distributor cap and see if the rotor turns when the engine is cranked. No movement would tell you the timing belt or chain (or possibly the cam itself) is broken. Another alternative is to remove the valve cover to see if the valves are opening and closing. This too will show you if the cam drive or cam is broken.

If a cam belt or chain has "slipped a tooth," throwing valve timing off, the valves will still open and close, and the rotor inside the distributor will still turn. But the engine won't develop enough compression to start. A compression check can help you find this kind of problem.

When I try to start my engine, I hear the starter spinning but the engine isn't cranking. What gives?

You have one of two problems: Either the starter drive on your starter is defective and is not engaging the flywheel to crank the engine, or the flywheel has some broken or damaged teeth that are preventing the starter from engaging.

Starters come in a variety of designs. On some, the solenoid is mounted on top of the starter. When you turn the key, the solenoid routes current to the starter motor and at the same time pulls a lever that slides the drive gear mechanism out so it will engage the flywheel and crank the engine. If the solenoid is weak or damaged, it may not be strong enough to overcome the spring tension that retracts the drive gear. So the starter spins but doesn't crank the engine.

On other starters, the solenoid is mounted remotely. When the starter motor starts to spin, it ratchets out so the drive gear will engage the flywheel and crank the engine. If the drive mechanism is damaged or hung up, the motor may spin but not crank the engine.

Regardless of what type of starter you have, it will have to come out for further inspection. The drive gear (which is sometimes referred to as a "Bendix drive") should move out when the starter starts to spin. The drive gear usually has a one-way clutch that is supposed to protect the starter against damage if someone keeps cranking the engine once it starts. The gear should turn one way but not the other. If the gear is locked up or turns freely either way, the drive is bad and needs to be replaced. If the drive can't be replaced separately, you'll have to replace the entire starter.

Starter Testing

If the drive seems okay, the starter should be "bench tested" using jumper cables or special equipment designed for this purpose.

CAUTION: Be careful because a starter develops a lot of torque. It should be held down with a strap or clamped in a vice (be careful not to crush or deform the housing!) before voltage is applied.

A simple no-load bench test can be performed with a battery and a pair of jumper cables to see if a starter motor will spin. But this test alone won't tell you if the starter is good or bad because a weak starter that lacks sufficient power to crank an engine at the proper speed (usually a minimum of 250 to 500 rpm) may still spin up to several thousand rpm when voltage is applied with no load.

A better method of determining a starter's condition is to have it tested on equipment that measures the starter's "amp draw." A good starter should normally draw a current of 60 to 150 amps, depending on the size or power rating of the starter. Some "high torque" GM starters may draw up to 250 amps, so refer to the OEM specifications to make sure the amp draw is within the acceptable range.

If the starter does not spin freely, or draws an unusually high or low number of amps, it is defective and replacement is required.

An unusually high current draw and low free turning speed typically indicate a shorted armature, grounded armature or field coils, or excessive friction within the starter itself (dirty, worn or binding bearings or bushings, a bent armature shaft or contact between the armature and field coils). The magnets in permanent magnet starters can sometimes break or separate from the housing and drag against the armature.

A starter that does not turn and draws a high current may have a ground in the terminal or field coils, or a frozen armature.

Failure to spin and zero current draw indicates an open field circuit, open armature coils, defective brushes or a defective solenoid.

Low free turning speed combined with a low current draw indicates high internal resistance (bad connections, bad brushes, open field coils or armature windings).

Can I replace the clutch myself?

You can if you have the proper tools and know-how. Changing a clutch is a big job on a rear-wheel drive car or truck, and an even tougher job on a front-wheel drive car or minivan.

On a rear-wheel drive vehicle, the driveshaft, transmission and bellhousing have to be removed from underneath the vehicle to get at the clutch. The clutch can then be unbolted from the flywheel and replaced. Resurfacing the flywheel is recommended -- and required if the flywheel is warped, grooved, badly worn, heat discolored and/or contaminated with grease or oil. That means the flywheel has to come out, too. If the flywheel is cracked, it should be replaced.

In addition to replacing the clutch, a new throw-out bearing is also recommended. Considering the labor involved to tear everything apart, it's risky to reuse an old throw-out bearing. It may not be noisy now, but it's hard to tell how many miles it might have left in it.

The pilot bushing in the end of the crankshaft that supports the transmission input shaft should also be inspected. Replacement is recommended if your vehicle has a lot of miles on it.

Reinstalling the transmission is the most difficult part of the job because the transmission is heavy (which means you'll need a floor or transmission jack, or a pair of strong arms). The clutch must also be perfectly aligned (with a pilot tool) so the transmission input shaft will slip into place, once everything has been bolted together.

With front-wheel drive, replacing the clutch is even more difficult because it involves pulling the engine or dropping the transaxle (both of which are major undertakings because of all the disassembly that's involved). For this, you'll need an engine hoist to pull the engine or a hoist or beam to support the engine from above while the transaxle comes out.

When I try to start my engine, I hear a clicking sound but nothing happens. Do I need a new starter?

Maybe, but the only way to know for sure is to check out the battery, solenoid and starter. If you hear a clicking noise, it means voltage is getting through to the solenoid. But there may not be enough voltage to spin the starter. So start with the battery and cables.

Is the battery at full charge? Are the battery cables clean and tight? Be sure to check both ends. Are the other electrical connections at the solenoid and starter clean and tight? It doesn't take much corrosion to choke off the flow of amps to the starter.

Next, check the wiring connections on the solenoid and starter. Are they clean and tight? Also check the solenoid ground connection or its mounting. Rust or corrosion here can interfere with the flow of amps, too.

Try bypassing the solenoid to see if the starter spins. If it spins, the problem is excessive resistance in the solenoid. Replace the solenoid. If the starter doesn't spin, or turns very slowly, however, the starter is dragging and needs to be replaced.

My engine starts and idles fine, but lacks power at high speed. What's wrong?

You most likely have one of two problems: a fuel line restriction or an exhaust restriction.

Fuel Restriction

A plugged fuel filter, crushed fuel line or clogged pickup screen inside the fuel tank can all starve your engine for fuel. Enough fuel may get through for the engine to start and run at low speed, but when more fuel is needed it can't get through resulting in loss of power at high speed. The same kind of problem can also be caused by a weak fuel pump. But fuel pumps usually quit altogether when they fail.

Inspect the fuel line from the tank to the engine. If you don't see any obvious damage, try replacing the fuel filter. If that doesn't help, blowing out the fuel line with compressed air from the engine towards the fuel tank may help dislodge a blockage and debris from the pickup screen. If the pickup screen in the tank is clogged with rust and debris, the tank will have to be removed so the screen can be replaced and the tank cleaned.

Fuel pressure can also be checked by teeing a suitable gauge into the fuel line. If pressure is very low (refer to a manual for the specs), the pump probably will need to be replaced.

Exhaust Restriction

As for an exhaust restriction, the easiest way to check for this condition is to hook up a vacuum gauge to a vacuum port on the intake manifold or throttle body. If vacuum is low and continues to drop as the engine runs, it's telling you pressure is backing up because of a restriction in the exhaust. The most likely culprit is a clogged catalytic converter.

If the converter has overheated, it may have melted internally. This would restrict the flow of gases through the converter and create a serious backpressure problem that would cause a loss of power at high speed. If the blockage is complete, the engine may start then die and not run at all.

Other causes here may include a crushed exhaust pipe (a visual inspection should find this easy enough), a double-walled pipe that has collapsed internally, or a muffler that has become clogged with rust (rare, because they usually blow out). If you suspect an exhaust restriction, temporarily disconnect the head pipe from the catalytic converter (which is no easy task because the bolts will probably be rusted solid). If the engine now runs normally, you have an exhaust restriction. Inspect the converter and replace it if needed.

NOTE: If the converter is plugged, it failed because something else caused it to overheat. Causes include misfiring spark plugs and leaky exhaust valves. The underlying problem needs to be identified and corrected before the converter is replaced otherwise the new converter will suffer the same fate.

I have a manual transmission. Does the fluid in it ever need to be changed?

Not usually. Some older import vehicles (like Volkswagen Beetles) recommended periodic lube changes for their gearboxes, but no modern car or light truck requires it. The reason why is because the oil stays relatively clean and runs fairly cool. Unlike the fluid in an automatic transmission that is being constantly churned (which generates heat) and contaminated by particles worn off the clutch plates, the fluid in a manual transmission or transaxle has life pretty easy. So it usually lasts the life of the transmission.

The only reason you might have for changing it would be if you were experiencing hard shifting problems during cold weather. Most older rear-wheel drive transmissions use a heavy gear oil like 75W, 80W or 90W, which can get pretty stiff at subzero temperatures. Changing to a lighter oil may improve shifting.

Most manual transaxles in front-wheel drive cars today use Dexron II automatic transmission fluid (ATF) to keep the gears lubed. ATF works well because it stays much more fluid at low temperatures. But ATF should not be substituted for gear oil. Always use the type of lubricant specified by the vehicle manufacturer.

Adding Oil

The only time you should have to add oil to a manual transmission or transaxle is if the tranny is leaking oil. If you see any grease or wetness around the tailshaft or driveshaft seals, the oil level in the transmission or transaxle should be checked because it may be low. WARNING: Allowing the transmission or transaxle to run too low on lubricant can ruin it.

My engine starts but dies after a couple of minutes and won't restart. What's wrong?

It sounds like the classic symptom of an exhaust blockage, probably due to a clogged catalytic converter. The converter can overheat and be damaged if excessive amounts of unburned fuel enter the exhaust system. This can happen if the engine has one or more fouled spark plugs or leaky exhaust valves. When this unburned fuel hits the converter, it sends temperatures soaring. The ceramic substrate or pellets that support the catalyst can melt and partially or completely block the flow of exhaust through the converter.

If a complete blockage occurs, the engine will start normally but the exhaust has no place to go. Backpressure quickly builds up and within a couple of minutes the engine quits running. Eventually, the pressure will seep out and allow the engine to restart after it has sit for some time. But the blockage will prevent it from running for long.

The cure here would be to replace the converter. But first, the underlying problem that caused the converter to overheat and fail needs to be diagnosed and corrected -- otherwise the new converter will suffer the same fate.

Other possible causes of this kind of condition include a crushed exhaust pipe, some prankster shoving a potato up your tailpipe, a collapsed inner wall in a double-walled head pipe, or a muffler that's obstructed with rust debris.

My engine is hard to start when it's cold. What's wrong?

If your engine has a carburetor, the hard starting problem is most likely choke related. If the engine cranks normally and the spark plugs are not worn or dirty, the choke probably needs to be repaired or adjusted.

The choke may be set too rich or too lean. Either way can cause hard starting. Inside the choke housing is a bimetal spring that regulates the tension on the choke according to temperature. If this spring is broken, the choke will not operate. If the choke linkage is rusty or jammed with varnish deposits or dirt, it may stick or not operate smoothly. Cleaning with carburetor spray or solvent may help alleviate a sticking problem.

On older fuel injected engines, a separate "cold start" injector is used to spray additional fuel into the intake manifold when a cold engine is first started. If this injector is not working, the engine can be hard to start. The injector is controlled by a timer and relay, so if either of these components is defective it can prevent the cold start injector from doing its job, too.

If your engine cranks slowly, your cold starting problem is not fuel related, but may be due to a weak battery, loose or corroded battery cables, or a weak starter.

Check for obvious problems first. Remove, clean and inspect the battery cables (both ends). Then check battery charge and condition. (More information on the condition of your battery and battery recharging is available.) If the battery charge is low, recharging the battery may temporarily solve your problem. But there's a reason why your battery is low. You probably have a charging system problem that requires further diagnosis. (More information on alternators is also available.) If your battery is more than four or five years old, it is probably near the end of its service life and needs to be replaced. A "load test" will tell you if it still has sufficient cranking capacity to provide reliable cold starting.

Slow cranking during cold weather (below freezing) can also be caused by oil that is too thick. A high viscosity oil such as straight 30 or 40 weight oil in the crankcase can make an engine very difficult to crank when the temperature drops. Switching to a lighter multiviscosity oil such as 10W-30 or 10W-40 should solve this problem.

When I try to start my engine, nothing happens. It won't even crank. All I hear is dead silence. What's wrong?

Assuming you're not deaf, you have a starting problem that may be due to a dead battery, a loose or corroded battery cable, a bad ignition switch, an open neutral safety switch, or a bad solenoid or starter.

Total silence usually means no juice is getting through to the starter. So start with the battery. Is is dead or does it still have a full charge? Are the battery cables loose, corroded or damaged? Be sure to check both ends of the cables, including the starter and ground connections.

If you don't find any obvious problems with the battery or its connections, voltage may not be passing through the ignition switch circuit to the starter solenoid. A voltmeter or 12 volt test light can help you see if voltage is reaching the solenoid when you turn the key.

If voltage isn't getting through, try jiggling the gear shift lever. Some vehicles may also have a safety switch on the clutch pedal that prevents the engine from starting unless the clutch pedal is depressed. Use your voltmeter or test light to isolate the component that needs to be replaced or adjusted. Sometimes the transmission or clutch linkage may need to be adjusted for the safety switch to work properly.

If voltage is getting through the ignition switch circuit, but the starter isn't doing anything, check the wiring connections on the solenoid and starter. Are they clean and tight? Try bypassing the solenoid. Refer to a shop manual for the proper terminals, then jump the one that routes voltage directly to the starter (usually B+ or BAT). If the starter spins, the problem is a bad solenoid (or poorly grounded solenoid). If nothing happens, the problem is a bad starter that needs to be replaced.

My engine is hard to start when it's hot. How come?

Hot starting problems are usually fuel related. When a hot engine is shut off, the temperature of the engine and everything on it continues to rise for awhile as the engine undergoes a period of "heat soak." This can cause fuel to boil inside the carburetor bowl, fuel lines and fuel filter. When you attempt to restart the engine, "vapor lock" obstructs the flow of fuel and the engine doesn't want to start.

This is much less of a problem on fuel injected engines because the fuel is usually under much higher pressure inside the injectors and fuel line. Even so, a fuel line routed near an exhaust manifold or a fuel rail that's exposed to a lot of heat may still suffer the same kind of problems.

Heat soak problems such as these can sometimes be cured by wrapping insulation around affected fuel lines, and/or installing an insulating spacer or heat shield under the carburetor.

A Seasonal Problem

Hard hard starting tends to be a seasonal problem, but may be worse in the early months of spring when refiners are switching fuel blends. Gasoline refiners produce fuel with a slightly lower volatility rating (called "Reed vapor pressure") during hot summer months because lower volatility fuel is less likely to boil and cause hot starting problems. During the winter, they switch to a higher volatility fuel because it makes cold starting easier. But if you still have "winter" grade fuel in your tank when warm spring weather arrives, you may experience some hot starting problems. The problem will go away, however, as soon as the refiners in your area switch to their summer grade fuel.

Other Causes

Hot starting problems can also be caused by cooling problems that allow your engine to run too hot (the pistons swell up and may scuff the cylinder walls), or excessive resistance in the starter motor that causes the engine to crank slowly. A starter "amp draw" test can be used to check the condition of your starter. Also, many starters have small "heat shields" to protect them from heat radiating from nearby exhaust pipes or manifolds. If the shield is missing, the starter may get too hot and bind up.

I have a manual transmission. Lately the clutch has started to slip. Does that mean I need a new clutch?

It depends. If your clutch has low miles on it (40,000 or less), chances are the slippage is due to one of two things: oil contamination or a misadjusted clutch linkage. If your clutch has a lot of miles on it (60,000 or more), chances are it's worn out and you need to replace it.

To rule out oil contamination as a possible cause of slippage, check under the rear of the engine and the bellhousing for oil leaks. If you see oil on the oil pan or bellhousing, the rear main oil seal is probably leaking. Other leak points include manifold and valve cover gaskets at the back of the engine, and the transmission input shaft seal.

If you've got an oil leak, don't replace the clutch until you've fixed the leak. Once the clutch linings have been contaminated by oil, there's no way to clean them. Replacing the clutch disk is the only way to restore proper clutch operation.

If you don't have a leak, check the linkage adjustment. Most cars with a cable linkage have an automatic adjusting mechanism that's supposed to maintain proper clearances. If anything, the cable would be too loose rather than too tight. But if someone has been playing around with the linkage adjustment, they may have gotten it too tight. The same goes for vehicles with hydraulic linkages. There's no way this type of linkage can cause slippage unless it is misadjusted by someone.

That leaves the clutch itself. Slippage can be caused by two things: worn facings or loss of spring tension in the pressure plate. Unless the clutch really has been abused or has a lot of miles on it, it's unlikely the pressure plate is weak. Normal wear reduces the thickness of the facings on the clutch disk, which in turn reduces the clamping force the pressure plate can apply to squeeze the disk against the flywheel. Replacing the clutch disk should cure the problem.

Even so, the clutch and flywheel should be carefully inspected when the parts are removed. If the pressure plate is worn or damaged, you'll need to replace that, too. Most experts recommend having the flywheel refaced to restore the friction surface. You can probably get by without refacing the flywheel -- but only if the flywheel is flat, smooth, clean and uncracked. Any grooves, heat discoloration, cracking or other damage would call for resurfacing or replacing the flywheel.

How can I tell if a rotor or drum really needs to be replaced?

A rotor must be replaced if it is at or below the minimum thickness specification or discard thickness stamped on the rotor (this same information can also be found in brake service manuals). Replacement is also necessary if a rotor cannot be resurfaced without exceeding the minimum thickness specification or the discard thickness specification. Replacement is also required if the rotor is cracked or damaged. Replacement may be recommended if a rotor has hard spots, is warped, or has been previously resurfaced for a warped condition.

A drum must be replaced if it is at or beyond the maximum inside diameter specification or discard diameter stamped on the drum. Replacement is also necessary if a drum cannot be resurfaced without exceeding the maximum diameter specification or discard diameter specification. Replacement is also required if a drum is cracked, damaged, bell mouthed or too far out of round for resurfacing.

My brakes are squealing. Does that mean I need a brake job?

Not necessarily. A certain amount of brake noise is considered "normal" these days because of the harder semi-metallic brake pads that are used in most front-wheel drive cars and minivans. This type of noise does not affect braking performance and does not indicate a brake problem. However, if the noise is objectionable, there are ways to eliminate it.

Brake squeal is caused by vibration between the brake pads, rotors and calipers. Pad noise can be lessened or eliminated by installing "noise suppression shims" (thin self-adhesive strips) on the backs of the pads, or applying "noise suppression compound" on the backs of the pads to dampen vibrations. Additional steps that can be taken to eliminate noise are to resurface the rotors and replace the pads.

Some brands of semi-metallic pads are inherently noisier than others because of the ingredients used in the manufacture of the friction material. Strange as it may sound (pardon the pun), cheaper pads are sometimes quieter than premium quality or original equipment pads. That's because the cheaper pads contain softer materials that do not wear as well. For that reason, they are not recommended. Premium quality pads should cause no noise problems when installed properly and will give you better brake performance and longer life.

Conditions that can contribute to a disc brake noise problem include glazed or worn rotors, too rough a finish on resurfaced rotors, loose brake pads, missing pad insulators, shims, springs or antirattle clips, rusty or corroded caliper mounts, worn caliper mounts, and loose caliper mounting hardware. Drum noise may be due to loose or broken parts inside the drum.

Most experts recommend new caliper and drum hardware when the brakes are relined, a thorough inspection of the calipers and rotors for any wear or other conditions that might have an adverse affect on noise or brake performance, and resurfacing the rotors (and drums) if the surfaces are not smooth, flat and parallel.

If you hear metallic scraping noises, on the other hand, it usually means your brake linings are worn out and need to be replaced -- especially if your brake pedal feels low or if you've noticed any change in the way your vehicle brakes (it pulls to one side when braking, it requires more pedal effort, etc.).

Some brake pads have built-in "wear sensors" that produce a scraping or squealing noise when the pads become worn. In any event, noisy brakes should always be inspected to determine whether or not there's a problem. And don't delay! If the pads have worn down to the point where metal-to-metal contact is occurring, your vehicle may not be able to stop safely, and you may score the rotors or drums to the point where they have to be replaced.

I feel a pulsation or vibration in my brake pedal every time I stop. But the brakes seem to work fine. Is anything wrong?

A pulsating brake pedal, which may be accompanied by a shuddering or jerky stop during normal braking, usually means a warped rotor or an out-of-round drum -- although it can sometimes be caused by loose wheel bearings, a bent axle shaft or loose brake parts. If the vehicle is equipped with ABS, however, some pedal feedback and noise is normal during panic stops or when braking on wet or slick surfaces. But you should not experience any ABS pedal feedback when braking normally on dry pavement.

The faces of a disc brake rotor must be parallel (within .0005 inch on most cars) and flat (no more than about .002 to .005 inches of runout) otherwise it will kick the brake pads in and out when the brakes are applied, producing a pulsation or vibration that can be felt in the brake pedal as the rotor alternately grabs and slips.

You can often see warpage in a brake rotor by simply looking at it. If the rotor has telltale glazed or discolored patches on its face, chances are it is warped. Measuring it with a dial indicator and checking it for flatness with a straight edge will confirm the diagnosis.

Resurfacing the rotor to restore the faces will usually eliminate the pulsation (unless the rotor is bent or is badly worn and has started to collapse in which case the rotor must be replaced). But it may only do so temporarily because of metallurgical changes that take place in the rotor. Hard spots often extend below the surface of the rotor. Resurfacing will restore the surface, but the hard spot may reappear again in a few thousand miles as the rotor wears. For this reason, GM and others recommend replacing warped rotors rather than resurfacing them.

Pedal pulsation caused by drum warpage isn't as common, but it can happen. A drum can sometimes be warped out-of-round by applying the parking brake when the brakes are hot. As the drum cools, the force of the shoes causes the drum to distort.

What causes a rotor to warp? Overtorquing or unevenly torquing the lug nuts with an impact wrench is a common cause. For this reason, most experts recommend using a torque wrench to tighten lug nuts when changing a wheel. There are also special torque-limiting extension sockets called "Torque Sticks" that can be safely used with an impact wrench to accurately tighten lug nuts. But a plain impact wrench should never be used for the final tightening of the lug nuts because most provide no control whatsoever over the amount of torque applied to the nuts.

Overheating can also cause rotors to warp. Overheating may be the result of severe abuse or dragging brakes. Defects in the rotor casting, such as thick and thin areas can also cause uneven cooling that leads to warpage. Hard spots in the metal due to casting impurities can be yet another cause.

What parts are generally replaced during a brake job, and why?

A traditional brake job (if there is such a thing) usually means replacing the front disc brake pads, resurfacing the rotors, replacing the rear drum brake shoes, resurfacing the drums, bleeding the brake lines (replacing the old brake fluid with new and getting all the air out of the lines), inspecting the system for leaks or other problems that might require additional repairs, and checking and adjusting the parking brake.

Some brake jobs may also include new hardware for the drums (recommended), and rebuilding or replacing the wheel cylinders and calipers (also recommended). But because of the added expense, these items may not be included in the package price or may only be done if the brake system really needs them (as opposed to doing them for preventative maintenance).

Hardware includes things like return springs, holddown springs and other clips and retainers found in drum brakes. It may also include bushings, pins and clips on disc brake calipers. Springs lose tension with age and exposure to heat. Most experts recommend replacing the hardware when relining drum brakes to restore proper brake action. If weak springs are reused, the shoes may drag against the drums causing accelerated shoe wear, a pull to one side, brake overheating and possible drum warpage. Other hardware that is badly corroded or faulty (such as the self-adjusters) may prevent the shoes from maintaining the correct drum clearance (which increases the distance the brake pedal must travel as the shoes wear), or the parking brake from functioning properly.

It's important to note that not all replacement linings are the same. There are usually several grades of quality in pads and shoes (good, better and best). The difference is in the ingredients that are used to manufacture the pads and shoes. The less expensive ones may cost less initially and save you a few dollars on your total bill, but you may not be happy with the way they wear and perform. All brake linings must meet minimum government safety standards. Even so, the cheaper grade of pads and shoes do not last as many miles as the premium grade of replacement linings, nor do they brake as effectively. They usually have a greater tendency to fade at high temperature and may increase the vehicle's stopping distance somewhat. Noise may also be a problem with cheap linings. The best performance and value for your money, therefore, is with the best or premium grade. Choose these when the brakes are relined.