Power Brake Assist: Testing and Inspection

PRECHECKS
^ Inspect all vacuum hoses and connections.
^ All unused vacuum connectors must be capped.
^ Hoses and their connections must be properly secured and in good condition with no holes, cracks, or collapsed areas.

OPERATION CHECK
1. Check the brake hydraulic system for leaks or insufficient brake fluid. Repair as necessary.
2. With the engine "OFF", place the transaxle in PARK (A/T) or NEUTRAL (M/T) and apply the parking brake.
3. Press the brake pedal several times to exhaust all of the vacuum from the system.
4. Press and hold the brake pedal.
5. Start the engine. If the vacuum system is operating, the brake pedal will move downward under constant foot pressure. If no movement occurs, the power brake booster system is not functioning.

POWER BRAKE BOOSTER TESTS
NOTE: If the power brake booster is noisy when the brakes are applied, it must be replaced.

1. Remove the vacuum booster hose from the power brake booster.
2. Place the transaxle in PARK (A/T) or NEUTRAL (M/T) and apply the parking brake.
3. Start the engine. Manifold vacuum should be available from the vacuum booster hose. If manifold vacuum is not available, inspect all of the hoses and hose connections. Repair as necessary.
4. Reconnect the vacuum booster hose and run the engine at fast idle for ten seconds.
5. Stop the engine and let the vehicle stand for ten minutes.
6. Apply the brake pedal with approximately 89 Nm (20 ft. lbs.) of force. The brake pedal feel should be the same as normal power assisted brake operation for at least one application.
- If the brake pedal feel is normal, then the power brake booster is OK.
- If the brake pedal feels hard, continue with the test.
7. Remove the vacuum booster hose from the power brake booster. Apply 57.3 kPa (17 in-Hg) of vacuum to the vacuum booster hose.
- If the vacuum does not leak off after ten minutes, replace the power brake booster.
- If the vacuum does leak off, replace the check valve and/or vacuum booster hoses.