Navigator 4WD V8-5.4L SOHC VIN 5 (2005)
Vacuum Brake Booster Check Valve: Description and Operation
Brake Booster
The power brake booster is a dual diaphragm, vacuum-assisted power brake booster.
^
reduces brake pedal pressure and travel distance.
^
is divided into separate vacuum and atmospheric pressure chambers by a diaphragm.
If the power assist fails, the brake system will continue to operate with increased brake pedal effort.
Hose and Check Valve
The power brake booster check valve:
^
closes when the engine is turned off.
^
in the closed position, traps engine vacuum in the power brake booster.
^
retains vacuum to provide several power-assisted brake applications with the engine off.
