Air Hydraulic Brake Power Assist Unit (Brake Servo)

Air hydraulic brake power assist unit (brake servo)




The air hydraulic brake power assist unit (brake servo) is of the vacuum-assisted type, and enhances the force the driver exerts on the pedal when braking. The enhancement ratio is 4.5:1. The vacuum is derived from the partial vacuum in the engine inlet manifold. The connection between the engine inlet manifold and the air hydraulic brake power assist unit (brake servo) has a non-return valve (1). This prevents air flowing back into the air hydraulic brake power assist unit (brake servo) if there is no partial vacuum in the inlet manifold.
There are two designs of air hydraulic brake power assist unit (brake servo), depending on whether the car is LH or RH drive. The air hydraulic brake power unit (brake servo) in RH drive models has a somewhat longer pressure hose.