A sign of a malfunction of the brake booster is an increase in the force on the pedal when braking compared to normal.
To complete the job you will need a rubber bulb.
Sequence of execution
1. Prepare the vehicle for operations (see "Preparing a car for maintenance and repair").
2. With the engine off, press the brake pedal 4-6 times.
3. While holding the pedal, start the engine. If the vacuum booster is working properly, the pedal should move slightly forward.
Otherwise, we check the tightness of the connections:
- check valve with vacuum booster and vacuum supply hose;
- vacuum supply hose with inlet pipe.
4. Check the operation of the check valve; if it is faulty, the vacuum in the vacuum cavity of the booster is not created. Having disconnected the hose from the check valve, we take it out of the rubber seal of the booster. We insert a rubber bulb into the hole of the larger diameter nipple and squeeze it. If the bulb remains in a compressed state, the valve is in good condition.
Otherwise, we replace the check valve.