Bronco L6-300 4.9L VIN Y 1-bbl (1983)
Vacuum Brake Booster: Description and Operation
The single and tandem vacuum boosters are self contained vacuum hydraulic power braking units. These are vacuum suspended units that use vacuum
and atmospheric pressure for their power.
On gasoline engine vehicles, vacuum is supplied through a fitting in the intake manifold. On diesel engine vehicles, vacuum is supplied through a
vacuum pump.
The three basic elements of the booster are the vacuum power chamber, mechanically actuated booster check valve and a hydraulic dual master cylinder
which supplies hydraulic pressure to the brake system.
The vacuum power chamber consists of a front and rear shell, diaphragm, diaphragm plate, hydraulic pushrod and vacuum diaphragm return spring.
The mechanically actuated booster check valve controls the degree of power brake application in accordance with foot pressure applied to the valve
operating rod through the brake pedal linkage. This valve is integral with the vacuum power diaphragm.
