Vacuum Brake Booster: Testing and Inspection

ON-VEHICLE INSPECTION





1. OPERATING CHECK
a. Depress the brake pedal several times with the ignition switch OFF and check that there is no change in the pedal reserve distance.
b. Depress the brake pedal and start the engine.
If the pedal goes down slightly, operation is normal.

Fig. 6 Booster Air Tightness Check:

2. AIR TIGHTNESS CHECK
a. Start the engine and stop it after 1 or 2 minutes. Depress the brake pedal several times slowly.
If the pedal goes down farthest the 1st time, but gradually rises after the 2nd or 3rd time, the booster is air tight.
b. Depress the brake pedal while the engine is running, and stop the engine with the pedal depressed.
If there is no change in the pedal reserve distance after holding the pedal for 30 seconds, the booster is air-tight.