Air Tightness Check

AIR TIGHTNESS CHECK
- Start engine and stop after one or two minutes.

Fig. 3 Air Tightness Check:

- Depress brake pedal several times slowly. If pedal drops the most on the first time, but gradually rises after the second or third time, booster is air tight.
- Depress brake pedal with engine running, then while depressing brake pedal stop engine.
- If there is no change in pedal reserve travel after holding pedal for 30 seconds, the booster is air tight.