Brake System Symptom Troubleshooting - Rapid Brake Pad Wear, Vehicle Vibration (After A Long Drive), Or High, Hard Brake Pedal
NOTE: Make sure that the caliper pins are installed correctly. The upper caliper pin and the lower caliper pin are different. If these caliper pins are installed in the wrong location, it will cause vibration, uneven or rapid brake pad wear, and possibly uneven tire wear. See the proper caliper pin location:
- 1. Brake system check:
1. Drive the vehicle to note if the brakes drag or the pedal becomes high and hard. This may take 20 or more brake pedal applications during an extended test-drive.
2. With the engine running, raise and support the vehicle , and spin all four wheels by hand.
Is there brake drag at any of the wheels?
YES
Go to step 2.
NO
Look for other causes of pad wear, high pedal, or vehicle vibration.
- 2. Brake booster check:
1. Turn the vehicle to the OFF (LOCK) mode, press the brake pedal several times to deplete the vacuum in the brake booster, and then spin the wheels again to check for brake drag.
Is there brake drag at any of the wheels?
YES
Go to step 3.
NO
- 3. Brake pedal position switch check:
1. Without removing the brake lines, unbolt and separate the master cylinder from the brake booster, then spin the wheels to check for brake drag.
Is there brake drag at any of the wheels?
YES
Go to step 4.
NO
Check the brake pedal position switch adjustment and pedal free play .
- 4. Master cylinder check:
1. Loosen the hydraulic lines at the master cylinder, then spin the wheels to check for brake drag.
Is there brake drag at any of the wheels?
YES
Go to step 5.
NO
Check the master cylinder reservoir for contamination in the brake fluid. If you find contamination, flush the entire brake system of all contaminated fluid, then replace all rubber parts in the brake system that were exposed to contaminated fluid. If the brake fluid is OK, replace the master cylinder .
- 5. Caliper check:
1. Loosen the bleed screws at each caliper, then spin the wheels to check for brake drag.
Is there brake drag at any of the wheels?
YES
Check the master cylinder reservoir for contamination in the brake fluid. If you find contamination, flush the entire brake system of all contaminated fluid, then replace all rubber parts in the brake system that were exposed to contaminated fluid. If the brake fluid is OK, disassemble and repair the caliper on the wheel(s) with brake drag.
NO
Look for and replace any damaged brake lines. If all brake lines are OK, replace the VSA modulator-control unit .