Vacuum Brake Booster: Description and Operation

Brake Booster
The power brake actuation system consists of the following components:
^ Brake booster assembly
^ Brake booster vacuum fitting

Pedal pressure is amplified by the brake booster. The brake booster uses engine vacuum from the intake manifold. The low pressure in the intake manifold is applied to a rubber diaphragm on the vacuum side of the brake booster chamber, which then pulls the piston rod in when the brakes are applied to supply a power assist. The piston rod is connected to the brake pedal.