Vacuum Brake Booster: Testing and Inspection

OPERATING CHECK

^ Depress brake pedal several times with engine off. After exhausting vacuum, make sure there is no change in pedal stroke.
^ Depress brake pedal, then start engine. If pedal goes down slightly, operation is normal.

AIRTIGHT CHECK





^ Start engine, and stop it after one or two minutes. Depress brake pedal several times slowly. Booster is airtight if pedal stroke is less each time.
^ Depress brake pedal while engine is running, and stop engine with pedal depressed. The pedal stroke should not change after holding pedal down 30 seconds.

REMOVAL

Exploded View Of Vacuum Booster Assembly:

CAUTION:
^ Be careful not to splash brake fluid on painted areas; it may cause paint damage. If brake fluid is splashed on painted areas, wash it away with water immediately.
^ Be careful not to deform or bend brake pipes during removal of booster.
^ It is necessary to remove ABS actuator and actuator bracket first because space around booster is limited.

INSPECTION

Output Rod Length Check

Testing For Vacuum At Booster:

1. Apply vacuum of 66.7 kPa (500 mm Hg, 19.69 in Hg) to brake booster with a hand vacuum pump.
2. Check output rod length.
3. Specified length . . . 10.275-10.525 mm (0.4045-0.4144 inches)