SEQUENCE OF WORKS
1. Stop the engine. Press the brake pedal several times and hold it down.
2. Start the engine. If the vacuum booster is working properly, 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 brake booster. In this case, be sure to replace the hose;
- a faulty check valve located in the vacuum hose. To check it, remove the hose from the 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 a vacuum does not form in the hose, the valve is faulty;
- leaky rubber gasket between the master brake cylinder and the brake booster. To replace the gasket, remove the master brake cylinder from the brake booster.
[The original article is available on the website: FORDBOOK.ru]