CAR VIBRATES AT HIGH SPEEDS

SYMPTOM SUMMARY
There is a vibration or shimmy at high speeds. The symptom may get worse as the vehicles speed increases and may or may not be present at lower speeds.

USUAL CAUSE The usual cause of a vibration or shimmy at high speed is improper tire balance or damaged tires.

DIAGNOSIS
Perform a careful visual inspection of each tire. Look for damage to the tires such as bulges or exposed steel belts. Inspect the wheels for dents, warpage or missing lug nuts. Check the tire pressure to ensure all tires are inflated evenly and to the correct pressure (check the owner's manual for the correct tire pressure - it should also be marked on the side of the tire). If the tires are in good condition, the most cost effective diagnosis is to have the tires computer spin balanced. This can be done at any tire retailer for a nominal charge. If the problem still persists, further diagnosis on the drive train should be performed. On rear wheel drive vehicles the U-Joints should be inspected. On front wheel drive vehicles, the drive axles and CV Joints should be inspected. Inspect the CV boots for tears or other damage indicating excessive joint wear.

PRECAUTIONS, TIPS, and NOTES Tires contain steel belts that, if exposed, are very sharp and can cut or cause injury to your skin. To prevent possible injury to your hands, do not run your hand over the tire during inspection.

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BRAKE WARNING LIGHT IS ON

SYMPTOM SUMMARY
The red brake warning lamp remains on after the vehicle is started.

USUAL CAUSE
The brake system is equipped with a red brake warning lamp that will illuminate under certain conditions. Some vehicles feature a float located in the master cylinder that will illuminate the brake warning lamp when the fluid level becomes too low. The light will also come on if hydraulic pressure is lost in one of the front or rear brake channels. Usually the proportioning valve contains the circuit that will turn the light on during hydraulic pressure failure. It will also automatically prevent any additional fluid to be routed to the leaking channel. This ensures there is an adequate brake fluid and pressure supply to the working channel. The light usually functions as the parking brake indicator lamp as well.

DIAGNOSIS
The first step in diagnosing this symptom is a visual inspection. Check the brake fluid level in the master cylinder to ensure it is within specifications. If the brake fluid level is low, you will need to inspect the system for leaks. You may refer to the "Brake Fluid Consumption" symptom for further details on the diagnosis of brake fluid loss. Ensure the emergency brake is completely released. On most vehicles, the emergency brake circuit will illuminate the bulb at a different intensity than the fluid level or pressure sensors. If the brakes function normally and have been inspected and found to be leak free, you should suspect a malfunction in the emergency brake light circuit. Apply and release the emergency brake and look for a change in the bulbs intensity. If no change occurs, this further confirms a malfunction in the emergency brake light circuit. This switch is usually located on the emergency brake mechanism and should be inspected for damage.

PRECAUTIONS, TIPS, and NOTES
Always use the proper brake fluid DOT rating when refilling or adding to the brake fluid master cylinder. Do not add more than 1 oz of fluid to the master cylinder without inspecting the system for leaks.

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MASTER CYLINDER IS LOW ON BRAKE FLUID

SYMPTOM SUMMARY
The master cylinder is low on brake fluid or the brake fluid continually goes low.

USUAL CAUSE
It is normal for the master fluid level to decrease slightly as the brake pads wear. As the brake pads wear, the pistons in the caliper extend to compensate for the friction wear. As this occurs, the caliper will store more brake fluid in the caliper cylinder and will decrease the fluid level in the master cylinder.

DIAGNOSIS
You will need to determine whether the fluid level is low in the master cylinder due to a fluid leak or the normal brake pad wear discussed above. A brake inspeciton should be performed to determine the cause. The calipers, wheel cylinders (on drum brakes) will need to be inspected. The brake pads and shoes (if equipped) should be inspected for signs of brake fluid contamination indicating a leak. Inspect the calipers for leaks at the rubber dust boot around the pistons. The dust boot on the wheel cylinder will have to be pulled off slightly to inspect for leaks. Check the hydraulic lines, proportioning valve and flexible hoses for leaks. Inspect the master cylinder where it mounts on the brake boosters for signs of leaks. Loosening the master cylinder retaining bolts and pulling it back slightly, will usually result in detection of a leak if present. If leaking, the fluid will run out of the mating surfaces. In this case, the master cylinder will require replacement. If there are no leaks present and the pads are worn, the most likely cause of the low brake fluid level is worn brake pads.

PRECAUTIONS, TIPS, and NOTES
The brake fluid level should be inspected at every oil change. If servicing the hydraulic system, use caution not to contaminate the system with dirt, debris or water. After the hydraulic system is serviced it will require bleeding. Refer to the manufacturers bleeding procedure to ensure all of the air is purged from the system. Always use the recommended brake fluid DOT rating. This information can be obtained from your owners manual or off the cap on the master cylinder.

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LOUD SQUEAL HEARD WHEN STEERING WHEEL IS TURNED

SYMPTOM SUMMARY
A loud squeal is emitted from under the hood when the steering wheel is turned.

USUAL CAUSE This symptom is usually caused by a loose or worn power steering belt.

DIAGNOSIS
With the help of an assistant, rotate the wheel all the way to the right or left while inspecting the drive belts. If the drive belts slip or squeal, service will be necessary. With the vehicle off, inspect the belts for wear or cracking. Some vehicles utilize a single serpentine belt that drives all of the accessories. These types of belts usually use an automatic tensioner that maintains the proper tension at all times. Inspect the belts for proper alignment to the pullies. A worn tensioner bearing can throw the belt out of alignment, causing abnormal belt wear or breakage.
Vehicles that use conventional "V" belts should be inspected for cracks or glazing. Over time, the inside surface of the V-belt can become glazed which can cause it to slip. A glazed belt will have a shine to it and feel hard and brittle. The tension of the V-belt should have about a 1/2" of deflection between its longest span. Over tightening a V-belt can lead to bearing failure in the driven accessory. Drive belts that are worn should be replaced and properly tensioned.

PRECAUTIONS, TIPS, and NOTES
Some vehicles use automatic tensioners that contain a large spring used to tension the drive belt(s). You should use caution when removing the belt from the tensioner. The tensioner can snap if not carefully held in place causing injury to your hands or arms. Always use caution when working under the hood. Some parts become very hot and can burn if touched. Rotating engine parts should be avoided by your body and loose clothing. Entanglement can cause severe injury.

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THERE IS A LIQUID ON THE FLOORBOARD OF MY CAR

SYMPTOM SUMMARYThere is a liquid present on the floorboard of the vehicle. The fluid may be green or clear and may be more noticeable after operating the heating or air conditioning system.

USUAL CAUSE Water present on the floorboard is usually caused by one of two things. Water is circulated into the passenger compartment through the heater core. The heater core is heated by the engine coolant. Air is then blown over the heater core, by the blower motor when the heater is on, to heat the passenger compartment. If this core develops a leak, it will usually leak into the passenger compartment floorboard. A heater core that has only a pin-hole sized leak, may not be leaking on the floor but may produce a fine mist or oily film that collects on the inside of the windshield. The evaporator core is also located in the same housing as the heater core. During normal air conditioning operation water will condense on the core. This water is normally drained out of the passenger compartment through a evaporator drain hose. The hose connects from the evaporator case inside the vehicle to the exterior of the vehicle at the rear of the engine compartment. If this hose becomes restricted, the water that condenses on the evaporator core will leak into the passenger compartment. This is usually clean water that will evaporate as opposed to coolant that will not evaporate and leave an oily film on the floorboard carpet.

DIAGNOSIS
You should verify the type of leak present. The heater core contains coolant that will feel oily and may have a green color to it. Water from the evaporator core will be clear with no color. Taking a white piece of paper and absorbing some of the fluid may help determine the fluid type.

CORRECTIVE ACTION
The only corrective action for a leak in the heater core is replacement. Do not use radiator stop leak or other sealant products in an attempt to fix a leak in the heater core. If the fluid is clear, the evaporator drain tube may be restricted or plugged. This hose is usually visible at the lower rear of the engine compartment on the right (passenger) side of the vehicle. You can inspect and/or clear the blockage by passing a piece of stiff wire through the end of the hose.

PRECAUTIONS, TIPS, and NOTES
A heater core that is leaking cannot be repaired and must be replaced. On most vehicles, replacing the heater core is an extensive and time-consuming project that may require special tools. The evaporator core that contains the refrigerant (Freon) for the air conditioner may be contained in the same housing as the heater core. On these vehicles, the housing is removed as a single unit and requires the refrigerant to be removed from the air conditioning system using special equipment. You should consult a repair manual specific to your vehicle or consult the advice of a professional technician prior to undertaking this job.

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FRONT END DIPS WHEN I STEP ON THE BRAKES

SYMPTOM SUMMARY
The vehicle dips forward when the brakes are applied.

USUAL CAUSE This symptom is usually caused by misadjusted rear brakes or weak shocks or struts.

DIAGNOSIS The shocks or struts can be tested by bouncing the front of the vehicle several times by placing your body weight on the front bumper. Once the vehicle starts the up and down motion, remove your weight from the front bumper. The up and down bouncing should come to a stop after only one or two additional bounces. If the the vehicle continues to bounce, the front shocks or struts may require replacement. A tire inspection can reveal worn shocks or struts as well. Bumps and dips accross the tread of the tire can indicate failed shocks or struts. If the shocks or struts are in good working order, the rear brake adjustment should be inspected. Inspect the parking brake to make sure it holds. If it does not hold, operate it several times. This will adjust the rear brakes on vehicles with self adjusters. If the parking brake still does not hold, a visual inspection of the brakes will be necessary to determine the cause.

PRECAUTIONS, TIPS, and NOTES Brake drums and rotors become extremely hot after vehicle operation. Use caution when working around hot braking components.

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CAR PULLS WHEN I STEP ON THE BRAKES

SYMPTOM SUMMARY
The vehicle pulls to the right or left when the brakes are applied.

USUAL CAUSE The usual cause of this symptom is contamination on the braking surface or a malfunctioning caliper. It can also be caused by different tire sizes on the right and left wheels. Worn suspension components can also cause this symptom.

DIAGNOSIS
If contamination, such as grease or oil is present on the left side, the vehicle will pull to the right since the left side will not provide the same braking force as the right. A visual inspection is the first step in diagnosing the problem. Perform a visual inspection on both sides of the vehicle. Check the following:

1. Inspect the tires for even tread wear and overall condition. Check to ensure tire inflation is the same and to specifications.

2. Inspect the brake rotors for contamination. On front wheel drive vehicles, inspect the CV boots for tears. If torn, the CV boot can allow the grease to contact the brake rotors.

3. Check the brake pads to ensure they are worn evenly on both sides of the vehicle. If one side is worn excessively, it could be caused by a sticking brake caliper. The brake caliper can slide or the pistons can stick, causing the brake caliper to maintain braking force on the caliper. This might be accompanied by a discolored brake rotor as well. Rotation of the wheels by hand with the vehicle on jackstands should be even on each side. On front wheel drive vehicles, the transmission should be placed in neutral. Ensure the emergency brake is engaged and proper jacking procedures are used. A wheel that requires excessive force to rotate by hand should be investigated further.

4. Inspect the rubber brake hoses that connect to the calipers. A collapsed brake line can expand under pressure, allowing the brake fluid to enter the caliper then collapse trapping the brake fluid in the caliper.

5. With the vehicle jacked up and the tires on, inspect the front end components for excessive wear. With one hand on the front of the tire and one on the wheel, try to turn the wheel right and left (as if in a turn, not rotational). The wheel may be able to be turned to the right or left, but it should be tight and have no free play back and forth. Perform the same test with one hand on the top and one on the bottom of the tire. With your hand on the top, pull out while pushing in with the hand on the bottom. Then do the opposite, pull out on the bottom and in on the top. There should be no play in the wheel. If play is present in both of the above tests, it is usually an indication of a worn wheel bearing. If there is only play from right to left, it is usually an indication of a worn suspension component such as a tie rod end or rack and pinion. Perfoming the test while inspecting the front end will usually reveal the worn component.

PRECAUTIONS, TIPS, and NOTES Brake rotors become extremely hot during braking. Use caution when working on the brakes shortly after vehicle operation. Always refer to manufacturers jacking procedures to prevent damage to the vehicle or injury to yourself.

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BRAKE PEDAL PULSATES WHEN I STEP ON IT

SYMPTOM SUMMARY
The brake pedal pulsates when applied. The symptom may be worse at higher speeds.

USUAL CAUSE
This symptom is usually caused by warped brake rotors. If the vehicle is equipped with four wheel disc brakes, it could be either the front or rear brake rotors. Excessive heat build up on the brake rotors can cause them to warp , causing a brake pedal pulsation. This can be the result of heavy stop and go driving. If the rear brakes are not adjusted properly, the demand on the front brakes will be higher which can also contribute to front rotor warpage. Some vehicle brake designs are also more prone to warpage than others. A warped brake rotor will cause the piston in the brake caliper to pulsate in and out when the brakes are applied. This in turn, causes the hydraulic brake fluid to transmit this pulsation to the master cylinder, then to the brake pedal.

DIAGNOSIS
If the symptom only occurs during braking and is worse at higher speeds, the most probable cause is warped brake rotors.

CORRECTIVE ACTION The corrective action is to replace or have the rotors machined (often referred to as surfaced or turned). It is recommended that the brake rotors be machined during replacement of the brake pads. This provides a parallel flat mating surface to the new pads. If the rotors are being machined to correct the pulsation, it is also recommended that the pads be replaced unless there is more than 50% life left on the existing pads.

PRECAUTIONS, TIPS, and NOTES
Brake rotors become extremely hot after vehicle operation and braking. Use caution when working on the braking system. Brake rotors have a manufacturers minimum thickness. Never machine a rotor beyond the minimum thickness. This will only contribute to additional warpage, since the rotor cannot adequately dissipate the heat generated during braking. The minimum thickness is usually stamped on the brake rotor, usually on the back side. The brake rotor should be replaced once it has reached or has become thinner than its minimum thickness.

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THE BRAKE PEDAL GOES TO THE FLOOR WHEN I STEP ON IT

SYMPTOM SUMMARY
The brake pedal goes to the floor when pressed. There may be little or no braking action when the pedal is depressed. The Red Brake Warning Lamp may be illuminated indicating a system failure.

USUAL CAUSE
Very low brake fluid or a defective Master Cylinder is the usual cause of this symptom. The master cylinder pressurizes the brake system when the pedal is depressed and provides hydraulic fluid to each of the wheels to apply the brakes. The braking system is designed to illuminate the Red Brake Warning lamp when a hydraulic failure is present.

DIAGNOSIS
If you have just performed other brake work on the vehicle and the hydraulic system was opened, the most probable cause is air in the system. The system will need to be bled according to manufacturers recomendations. The first step in diagnosing this symptom is to inspect the brake fluid level at the master cylinder. If the fluid level is low, the system will need to be inspected for leaks. The calipers, wheel cylinders (on drum brakes) will need to be inspected. Brake pads that are completely worn can cause low fluid level. This is a result of the caliper pistons being completely extended, causing most of the brake fluid to reside in the calipers. The brake pads and shoes (if equipped) should be inspected for signs of brake fluid contamination indicating a leak. Inspect the calipers for leaks at the rubber dust boot around the pistons. The dust boot on the wheel cylinder will have to be pulled off slightly to inspect for leaks. Check the hydraulic lines, proportioning valve and flexible hoses for leaks. Inspect the master cylinder where it mounts on the brake booster for signs of leaks. Loosening the master cylinder retaining bolts and pulling it back slightly, will usually result in detection of a leak if present. If leaking, the fluid will run out of the mating surfaces. In this case, the master cylinder will require replacement. If there are no fluid leaks present or the fluid level is normal and the brake pads and shoes (if equipped) are in good condition, the most probable cause of the symptom is a defective master cylinder.

CORRECTIVE ACTION Determining the cause of the failure will dictate what corrective action is necessary. If the hydraulic system needs to be serviced, as with replacement of the master cylinder, it will need to be bled of all the air once it has been resealed. Refer to the manufacturers specific bleeding procedures.

PRECAUTIONS, TIPS, and NOTES
If the vehicle is equipped with ABS, certain ABS components can cause this symptom. In this case, the system should be serviced according to manufacturers recommendations. If servicing the hydraulic system, use caution not to contaminate the system with dirt, debris or water. Always use the recommended brake fluid DOT rating. This information can be obtained from your owners manual or off the cap on the master cylinder.

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BRAKES MAKE A GRINDING NOISE WHEN APPLIED

SYMPTOM SUMMARY
The brakes emit a grinding noise when applied. The braking action may not be as effective as normal.

USUAL CAUSE This symptom is usually caused by metal to metal contact between the brake pad and rotor or brake shoe and drum. The brake pads and shoes have a metal surface that the friction surface is mated to. Once the friction material is worn off, the metal surface will contact the rotating surface of the drum or rotor. This metal to metal contact usually results in a grinding noise.

DIAGNOSIS A visual inspection of the brake system will indicate the cause of the noise. The brake pads and rotors should be inspected for damage. If the rotor is excessively worn beyond the manufacturers minimum thickness, the rotor will have to be replaced. If the drums have grooves worn in them beyond the manufacturers maximum diameter, they will require replacement.

PRECAUTIONS, TIPS, and NOTES When replacing the brake pads or shoes, it is recommended that the brake rotors and drums be machined (often referred to as surfaced or turned). This will provide a flat mating surface for the new pads or shoes which will prevent brake squeal. A high quality anti-squeak compound should be applied sparingly to the back side of the new pads. Some vehicles use metal shims between the pad and the caliper. These shims should be replaced or cleaned and re-installed. Brake rotors and drums become extremely hot after vehicle operation and braking. Use caution when working on the braking system. Brake rotors and drums have a manufacturers minimum thickness and maximum diameter specifications. Never machine a rotor or drum beyond the manufacturers specifications. The minimum thickness and maximum diameter specification is usually stamped on the brake rotor or drum.

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ODOR COMING FROM AIR CONDITIONING VENTS

SYMPTOM SUMMARYA mild to severe odor that emanates from the air conditioning vents shortly after starting the air conditoning. The odor may diminish after the air conditioner has been running for several minutes but reoccurs at next operation.

USUAL CAUSE Odor from the air conditioning is usually caused by mildew growth on the air conditioning evaporator core. During normal A/C operation, water condenses on the evaporator core. This water is drained off through a tube located at the bottom of the evaporator housing in the passenger compartment. Small amounts of water will remain on the evaporator core after the air conditioning is turned off. On a hot day, this moisture inside the evaporator case can cause mildew growth on the evaporator core. This mildew growth can cause a foul odor through the air conditioning vents during the first few minutes of air conditioning operation. It can smell like dirty feet or stinky socks.

CORRECTIVE ACTION
There are several industrial chemicals that can be used to kill the mildew growth, but it will usually require perodic treatments at the peak of the air conditioning season. Household mildew sprays can also help by spraying a fine mist into the vent inlets, usually located on the exterior of the vehicle near the windshield. This procedure should be done while the fan is on high, all windows in the vehicle open and the recirculation switch on the dash set to outside air. The purpose is to draw the cleaner past the evaporator core killing any mildew present on the surface. Use the cleaner sparingly and never spray it directly into the vents located in the passenger compartment.

PRECAUTIONS, TIPS, and NOTES
Completely ventilate the vehicle of any cleaner fumes prior to driving with the windows up. Use caution with the cleaner not to damage the paint or interior of the vehicle.

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ANTI-LOCK BRAKE LIGHT STAYS ON AFTER ENGINE IS STARTED

SYMPTOM SUMMARY
The "ABS" or "Anti-Lock Brakes" light remains on after the engine is started and remains on or flashes.

USUAL CAUSE
The Anti-Lock brake system is designed to rapidly modulate the braking action during a panic stop. This prevents the wheels from locking up and maintains vehicle control and stability. An ABS control module monitors the wheel speed and other various sensors to determine when wheel lock-up is about to occur. The ABS module continually performs diagnostics to ensure that the system is functional. When a malfunction occurs, the ABS module will illuminate or flash the ABS or Anti-Lock light on the dash panel to alert the driver. During start up, the module will illuminate the light as a self test. Shortly after the engine is started, the light should go out indicating the system is functional. If the light remains on the ABS Module has detected a system failure. On most vehicles, the ABS system will not be functional while the light is illuminated. Usually, normal braking will result unless the failure is related to a component that is used for both normal braking and anti-lock braking. If the Red Brake light is also on, normal braking may be degraded as well indicating a system wide failure.

DIAGNOSIS
On almost all ABS systems the module will store a diagnostic trouble code that relates to the circuit or component that has failed. The diagnosis will require the module to be placed in self diagnostic mode, which will result in it transmitting the stored diagnostic code. Once the code is received, the diagnosis should focus on that particular component or sensor. A vehicle specific service manual will indicate how the module is placed into diagnostic mode and will indicated what circuit or component relates to what code. Often a special scan tool, similar to a hand held computer, is required to interface with the module.

CORRECTIVE ACTION Once the code has been retreived from the modules memory, that component or circuit will require service. Some components, such as the wheel speed sensors, are usually simple to replace. However, other components such as the hydraulic modulator and control solenoids require special tools and special bleeding procedures to ensure proper operation.

PRECAUTIONS, TIPS, and NOTES
If the ABS light is on, the failure should be corrected as soon as possible. If possible, you should leave repairs to the ABS system to trained service personnel that are equipped with the correct tools and equipment. The Hydraulic Modulator may contain brake fluid pressurized to over 1,500 psi, that if not properly bled, can pose significant danger to someone servicing the system.

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SQUEAK OR SQUEAL FROM WHEEL

SYMPTOM SUMMARY
There is a squeak or squeal sound coming from the wheel area when the vehicle is in motion. The symptom may be worse when the brakes are applied.

USUAL CAUSE
A squeak or squeal from the wheel area can be caused by worn brake pads or uneven braking surfaces between the pad and the brake rotor. The brake pad is equipped with a metal wear indicator that contacts the brake rotor when the pads become worn beyond their useful service life. This wear indicator is designed to emit a high pitched squeak when it contacts the brake rotor to indicate that brake service is needed. If the brakes are severely worn, the indicator may contact the rotor at all times emitting the squeak even when the brakes are not applied.

DIAGNOSIS
A visual inspection of the brakes will indicate if brake service is necessary. If the pads are worn to the wear indicator, replacement will be necessary. If the pads still have a useful service life left, an anti-squeak compound may be applied to the backside of the pad (metal side).

PRECAUTIONS, TIPS, and NOTES
When replacing the brake pads, it is recommended that the brake rotors be machined (often referred to as surfaced or turned). This will provide a flat mating surface for the new pads which will prevent brake squeal. A high quality anti-squeak compound should be applied sparingly to the back side of the new pads. Some vehicles use metal shims between the pad and the caliper. These shims should be replaced or cleaned and reinstalled. Brake rotors become extremely hot after vehicle operation and braking. Use caution when working on the braking system. Brake rotors have a manufacturers minimum thickness. Never machine a rotor beyond the minimum thickness. This will only contribute to warpage since the rotor cannot adequately dissipate the heat generated during braking. The minimum thickness is usually stamped on the brake rotor, usually on the back side. The brake rotor should be replaced once it has reached or has become thinner than its minimum thickness.

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EMERGENCY BRAKE OR PARKING BRAKE WON'T HOLD

SYMPTOM SUMMARY
The emergency brake or parking brake will not hold.

USUAL CAUSE The usual cause of this symptom is improper rear brake adjustment. Many vehicles utilize a self adjusting rear brake system. This system maintains adequate brake tension on the rear brakes so that when the parking brake is engaged, the rear brakes hold the vehicle in place.

DIAGNOSIS
The self adjusters re-tension the rear brakes each time the parking brake is engaged or the vehicle is driven in reverse and the brakes are applied. This system needs to be used frequently to maintain the proper rear brake tension. Often, the parking brake is used infrequently, especially on vehicles equipped with an automatic transmission. Due to this, the rear brakes wear and will result in excessive distance between the rear friction material and the rotor or drum. When the parking brake is applied, this excessive distance prevents the friction material from completely and tightly contacting the rotor or drum. This will prevent the parking brake from holding the vehicle.

CORRECTIVE ACTION
You should apply and release the parking brake several times to activate the self adjusters. This may take as many as 10 to 15 times to bring the rear brakes into adjustment. If this is not effective, apply the brakes abruptly while traveling in reverse at low speed. If the parking brake still will not hold, the rear brakes will have to be inspected and adjusted manually. Once the brakes are in proper adjustment, you should utilize the parking brake on a frequent basis to ensure they remain properly adjusted.

PRECAUTIONS, TIPS, and NOTES Brake rotors and drums become extremely hot after vehicle operation and braking. Use caution when working on the braking system.

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I HEAR A LOUD SQUEAL WHEN A/C IS TURNED ON

SYMPTOM SUMMARY
A loud squeal is produced when the A/C is turned on.

USUAL CAUSE
This symptom is usually caused by a loose or worn air conditioning compressor belt. When the A/C is activated the compressor is engaged. This places a load on the engine and the drive belt that rotates the compressor. If the belt is loose or worn the belt can slip on the compressor pulley and emit a loud squeal.

DIAGNOSIS
The drive belts should be inspected for proper tension and wear. A properly tensioned belt should have aproximately 1/2" of deflection at its greatest span between pulleys. Inspect the belt for wear. Belts can become glazed on the inside drive surface which can cause them to slip, which produces the loud squeal. Some vehicles use an automatic tensioner that contains a large spring that keeps constant pressure on the belt. This system automatically tensions the belt to the proper tension. This system is often used on vehices that use a serpentine belt. This type of system uses one belt to drive many accessories.

PRECAUTIONS, TIPS, and NOTES
Use caution when working around hot or rotating engine parts.

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CAR PULLS TO ONE SIDE WHILE DRIVING

SYMPTOM SUMMARY
The vehicle pulls to the right or left. The problem may be worse at higher speeds. If the symptom only occurs during braking, refer to the "Vehicle Pulls When Brakes Are Applied" symptom.

USUAL CAUSE This symptom usually indicates that a front end alignment is needed. It can also be caused by a tire pull or improperly inflated tires.

DIAGNOSIS
Tire pressure and condition should be checked and corrected as necessary. The tires should be rotated from front to rear and the vehicle should be road tested. If the symptom still persists, the front end alignment will have to be inspected and adjusted as necessary.

PRECAUTIONS, TIPS, and NOTES When rotating tires, use the manufacturer's jacking procedures to prevent damage to the vehicle and/or injury to yourself. Use caution when working around a jacked vehicle. Always use jack stands and never rely on the jack as a single method to support the vehicle during servicing.

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