Checking the performance of the vacuum booster (VAZ-2108)

Press the brake pedal 5-6 times with the engine off to create a vacuum in cavities A and B (see figure 105) the same pressure, close to atmospheric. At the same time, by the force applied to the pedal, it is determined whether the valve body is jammed. Stopping the brake pedal in the middle of its travel, start the engine.

If the vacuum booster is in good working order, the brake pedal should "go forward" after starting the engine. If this does not happen, check the fastening of the hose tip, the condition and fastening of the tip flange in the booster, the hose to the tip and the nipple of the engine intake pipe, since loosening the fastening or damaging them sharply reduces the vacuum in cavity A and the efficiency of the booster.