Component Tests

Component Tests

Brake Master Cylinder - Bypass Condition

1. Inspect the master cylinder. Refer to Brake System Inspection Brake System Inspection.

2. Disconnect the brake tubes from the master cylinder.

3. Plug the outlet ports of the master cylinder.

4. NOTE: Make sure that the outlet port plugs do not show signs of leakage.
Lightly apply the brakes and hold for 10 seconds. Release the brakes and then reapply with heavy force. If brake pedal height cannot be maintained, the brake master cylinder has an internal leak and a new brake master cylinder must be installed.

- If brake pedal height is maintained, reinstall brake tubes and tighten to specifications. Refer to Specifications. After installation, bleed the brake system. Refer to Brake System Bleeding Brake System Bleeding.


Brake Master Cylinder - Compensator Port

1. Inspect the master cylinder. Refer to Brake System Inspection Brake System Inspection.

2. With the vehicle in NEUTRAL, position it on a hoist.

3. Apply and release the brakes.

4. With the brakes released, attempt to rotate each wheel and check for any brake drag.
- If an excessive amount of brake drag exists at multiple wheels, continue to Step 5.

- If an excessive amount of brake drag exists at only one wheel, it indicates a possible seized brake caliper, brake wheel cylinder or parking brake component. Repair or install new components as necessary.


5. Check the brake stoplamp switch and the brake pedal free play to verify that the brake pedal is not partially applied.

6. Loosen the brake master cylinder nuts and position the brake master cylinder away from the brake booster.

7. With the brakes released, attempt to rotate each wheel and check for any brake drag.
- If the brake drag is no longer present, install a new brake booster.

- If the brake drag is still present, install a new master cylinder.