Power Brake Booster

DESCRIPTION






The power brake booster assembly mounts on the engine side of the dash panel. It is externally connected to the brake pedal by an input push rod extending out the rear of the booster. The master cylinder is bolted to the front of the power brake booster assembly.
A vacuum check valve is mounted on the power brake booster body. A vacuum line connects the booster (check valve) to the intake manifold. Depending on the engine combination, different vacuum hose routings are required.






The power brake booster can be identified by the tag attached to the body of the booster assembly. This tag contains the following information:
^ the production part number
^ the date it was built
^ who manufactured it

NOTE: The power brake booster assembly is not a repairable part and must be replaced as a complete unit if it is found to be faulty in any way. The power booster vacuum check valve is not repairable but can be replaced as an assembly.

OPERATION
The purpose of the power brake booster is to reduce the amount of force required by the driver (foot-pedal pressure) to obtain the required hydraulic pressure in the brake system to stop the vehicle. This vehicle utilizes a Bosch power brake booster to accomplish this task in all brake applications.
The power brake booster is vacuum operated. The vacuum is supplied from the intake manifold on the engine through the vacuum hose and power brake booster check valve.
As the brake pedal is pressed, the power brake booster's input rod moves forward. This opens and closes valves in the power brake booster, creating a vacuum on one side of a diaphragm and allowing atmospheric pressure to enter on the other. This difference in pressure forces the output rod of the power booster out against the primary piston of the master cylinder. As the pistons in the master cylinder move forward this creates the hydraulic pressure in the brake system.