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.