F 150 4WD Pickup V8-281 4.6L VIN W EFI (1997)
Brake Proportioning/Combination Valve: Description and Operation
Master Cylinder Control Valve
PURPOSE
The brake master cylinder fluid control valve regulates the hydraulic pressure in the rear hydraulic circuit. It is located on the brake master cylinder and
is screwed into the rear most outlet port.
OPERATION
When the brake pedal is applied, the full brake pressure passes through the brake master cylinder fluid control valve to the rear hydraulic circuit until the
valve's split point is reached. Above its split point, the brake master cylinder fluid control valve begins to reduce the hydraulic pressure to the rear
brakes, creating a balanced braking condition between the front and rear wheels to minimize rear wheel lockup during hard braking.
In case of front brake system malfunction, the brake master cylinder fluid control valve has a bypass feature which allows full hydraulic pressure to the
rear brake system.
