Brake System Symptom Troubleshooting

Brake System Symptom Troubleshooting

Rapid brake pad wear, vehicle vibration (after a long drive), or high, hard brake pedal

NOTICE
If the brake system indicator is on with the buzzer sounding, do not drive the vehicle. Check the advanced hydraulic booster system Initial Inspection and Diagnostic Overview.

NOTE: Make sure that the caliper pins are installed correctly. Upper caliper pin and lower caliper pin are different. If these caliper pins are installed in the wrong location, it will cause vibration, uneven or rapid pad wear, and possibly uneven tire wear. For proper caliper pin location: Front caliper Front Brake Caliper Overhaul, rear caliper Rear Brake Caliper Overhaul.

1. Check the advanced hydraulic booster system Initial Inspection and Diagnostic Overview. Make sure the indicators are not turned on.

2. 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.

3. 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 4.

NO -

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

4. Turn the ignition switch to LOCK (0), press the brake pedal to deplete the advanced hydraulic booster system, then spin the wheels again to check for brake drag.

Is there brake drag at any of the wheels?

YES -

Go to step 5.

NO -

Replace the servo unit Service and Repair.�

5. Remove the brake pedal position switch, 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 brake pedal position switch adjustment and pedal free play Adjustments.�

6. 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 7.

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 Service and Repair.�

7. Loosen the bleed screws at each caliper or wheel cylinder, 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 or wheel cylinder on the wheel(s) experiencing brake drag.�

NO -

Look for and replace any damaged brake lines. If all brake lines are OK, replace the ABS or VSA modulator-control unit: ABS, VSA Service and Repair.�