4 Inspection of Vacuum Check Valves
The vacuum check valve is located between the engine intake manifold and the vacuum booster. The vacuum of the engine intake manifold reaches the vacuum booster through the vacuum check valve, but the vacuum of the vacuum booster cannot be returned through the valve. Therefore, the function of the vacuum check valve is to ensure that the vacuum in the vacuum booster can maintain a certain period of time after the engine is stopped, and maintain an effective power-assisted braking. When checking, first idle the engine, then turn off the engine and wait for 5 minutes, then step on the pedal to apply the brakes. At least one pedal stroke should help. If there is no assistance during the first pedaling, the one-way valve has a leak failure. Further inspection, the one-way valve was removed, and the mouth was blown toward the inlet manifold end of the one-way valve. The air flow should not pass through at all. When the vacuum check valve reversely leaks, it should be replaced. In addition, the opening and closing of the vacuum check valve is blocked or stuck and should also be replaced.
5 vacuum booster air valve check
If there is a leakage failure in the vacuum booster air valve, when the car is not braked, part of the air enters into the B cavity and causes a pressure difference between the B and A cavity on both sides of the diaphragm, resulting in automatic operation of the booster, resulting in more retarded driving force of the wheel. Big. This kind of fault has a great degree of concealment, leading to a serious decline in the power and economy of the car. According to investigations, many drivers do not know when such a breakdown occurs. Some of them know that the wheel driving force is too large and the hub heat is serious. However, when the cause of the fault is found, the brake is often improperly adjusted. There is little doubt that the vacuum is incorrect. Booster problem. There are two ways to check.