1. Squeeze out the brake pedal with force down to the stop at least 5 times with the engine off, then start the engine with the brake pedal depressed. Now the pedal under the foot should be noticeably moved down.
2. Disconnect the hose from the vacuum brake booster if the desired effect is not achieved.
3. Start the engine. By placing your finger on the end of the hose, verify that there is reduced pressure generated by the pump when the engine is running. If there is no reduced pressure, then check the condition of the vacuum hose, make sure there is no damage to i ieM. Replace hose if necessary. Tighten all hose clamps.
Diesel vehicles
4. Disconnect the hose from the vacuum pump of the brake booster and, applying a finger to the end of the hose, make sure that there is a reduced pressure that should be created by the pump.
If there is low pressure, then measure it. Replace the brake booster if necessary (In workshop).
Attention! Change the check valve together with the booster, because if the check valve is defective, fuel vapors penetrating into the vacuum booster damage the booster membrane.