Hatchback 4WD F4-1781cc 1.8L (1983)
Vacuum Brake Booster: Description and Operation
The brake booster is located in line between the master cylinder and the brake pedal. It serves to mechanically boost the force pushing the pistons of
the master cylinder.
The brake booster consists of a power cylinder section and a power piston section. The power cylinder is made up of a front shell, rear shell and a
diaphragm. The front and rear shells are connected with the diaphragm placed in between the two. The power cylinder chamber is closed to the
atmosphere and the left and right chambers of the diaphragm are kept sealed.
The power piston is guided by a tube which slides along the rear shell. A push rod, which is used to move the primary piston of the master cylinder, is
attached to the left of the power piston. The right end of the push rod closely contacts the rubber reaction disc built into the power piston.
The valve plunger is clinched by the operating push rod and is pushed against the right wall of the power piston chamber by the valve return spring.
The check valve maintains a constant level of vacuum pressure within the brake booster that utilizes the intake manifold vacuum pressure for power.
