Vacuum Brake Booster: Testing and Inspection

Perform this procedure with the parking brakes applied.

1. Start engine, then stop after one or two minutes of running time.
2. Depress brake pedal several times with normal force.
3. If pedal travel decreases the more times the brake pedal is depressed, the brake booster and vacuum lines are functioning correctly.
4. If pedal travel does not decrease and remains firm, check brake booster vacuum hose and check valve for proper operation.
5. If vacuum hose and check valve are functioning properly, replace vacuum booster assembly.