Symptom Related Diagnostic Procedures

Brake System Symptom Troubleshooting - Rapid brake pad wear, vehicle vibration (after a long drive), or high, hard brake pedal

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 B and lower caliper pin A are different. If the pins are installed in the wrong location, it will cause vibration, uneven or rapid brake pad wear, and possibly uneven tire wear. For proper caliper pin location Front Brake Caliper Overhaul.

1. Drive the vehicle until the brakes drag or until the pedal is high and hard. This can take 20 or more brake pedal applications during an extended test-drive.

2. With the engine running, raise and support the vehicle Service and Repair, and spin all four wheels by hand.

Is there brake drag at any of the wheels?

YES -

Go to step 3.

NO -

Look for other causes of pad wear, high pedal, or vehicle vibration.�

3. Turn the ignition switch to LOCK (0), 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 4.

NO -

Replace the brake booster Service and Repair.�

4. 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 5.

NO -

Check the brake pedal position switch adjustment and pedal free play Adjustments.�

5. 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 6.

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. If the brake fluid is OK, replace the master cylinder Service and Repair.�

6. 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 Service and Repair.�