Checking the vacuum brake booster

SEQUENCE OF WORK

1. Stop the engine. Press the brake pedal several times and keep it pressed.

2. Start the engine. With a working vacuum booster, the brake pedal should move forward after starting the engine. If this does not happen, the following reasons are possible:

- Leakage of the vacuum hose connecting the intake manifold and the vacuum brake booster. In this case, be sure to replace the hose;

- Malfunction of the non-return valve located in the vacuum hose. To check it, remove the hose from the vacuum brake booster while the engine is idling. If you do not hear rhythmic suction noises, close the open end of the hose with your finger. If there is no vacuum in the hose, then the valve is faulty;

- Leakage of the rubber gasket between the main brake cylinder and the vacuum brake booster. To replace the gasket, remove the brake master cylinder from the brake booster.