- A) Depress the brake pedal several times with the engine off and check that the pedal reserve does not change.
- b) Press the brake pedal and start the engine. If the brake pedal smoothly goes down, the vacuum booster is operational.
2. Air tightness test.
- A) Start the engine and stop after one or two minutes of operation. Slowly press the brake pedal several times. If the pedal drops lower on the first press than on the second and third, then the vacuum booster is sealed.
- b) Depress the brake pedal with the engine running and stop it with the pedal depressed. If the distance between the priest and the depressed pedal does not change within thirty seconds, the vacuum booster is sealed.