E 350 Van V8-7.3L DSL Turbo VIN F (1995)
Brake Proportioning/Combination Valve: Description and Operation
Proportioning Valve
PURPOSE
A proportioning valve, where used, is integral to the master cylinder. It proportions pressure to the rear system.
OPERATION
The brake pressure control valve regulates the hydraulic pressure in the rear brake system. It is located between the rear brake system's inlet and
outlet ports in the main valve. When the brake pedal (2455) is applied, the full brake fluid pressure passes through the brake pressure control valve
to the rear brake system until the valve's split point is reached. Above its split point, the brake pressure 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 lock-up during hard
braking.
In case of the 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.
