Pic. 6.12. Checking the brake pedal travel with the engine off
Depress the brake pedal several times with the engine off and check that the pedal travel does not change (pic. 6.12).
Press the brake pedal and start the engine. If the brake pedal smoothly goes down, the vacuum booster is operational.
Pic. 6.13. Checking the brake pedal travel with the engine running
Start the engine and stop after one to two minutes of operation. Slowly press the brake pedal several times (pic. 6.13).
If the pedal drops lower on the first press than on the second and third, the vacuum booster is sealed.
Depress the brake pedal with the engine running and stop it with the pedal depressed. If the distance between the floor and the depressed pedal does not change within thirty seconds, the vacuum booster is sealed.