How Does a Vacuum Brake Booster Work?

Background

Vacuum brake boosters are located between the firewall and brake master cylinder of a vehicle. They're silent and don't use gasoline or electricity. They function to allow cars to be able to stop with a light touch onto the brake pedal. Before vacuum brake boosters, you had to slam down on the brake pedal to make a car stop.

Function

Contemporary vacuum brake boosters work with the use of vacuum power; hence the name. Engines produce vacuum power whenever they run. The brake booster gets the engine vacuum with the assistance of a rubber hose that comes from the intake manifold. Then the vacuum is used to increase the pressure that's applied to the pedal, making it much easier to stop the vehicle without having to stomp on the brakes. This allows the vehicle to stop quickly. The vacuum brake boosters take the vacuum of the engine and multiply the applied force from the foot, essentially.

Check Valves

Check valves are one component of vacuum brake boosters. These exist to prevent engine vacuum loss in the situation of a stalling car. They're located in the circuit of the brake booster. They contain sufficient vacuum power to be able to offer a complete boost for approximately two or three touches of the pedal. The check valve prevents leakage of the vacuum as well. Leaks are the No. 1 culprit in having to replace units for brake boosters.