PB 150 V8-318 5.2L VIN T 2-BBL (1983)
Brake Proportioning/Combination Valve: Description and Operation
Proportioning Valve
Fig. 23 Type 1, Combination Valve
Fig 2 Brake Warning Switch / Hold Off Valve (Cut Away View)
NOTE: This valve is part of a combination valve. See Application and ID.
The proportioning valve section transmits full input pressure to the rear brakes up to a certain point, called the split point. Beyond that point it
reduces the amount of pressure increase to the rear brakes according to a certain ratio.
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On light pedal applications, approximately equal brake pressure will be transmitted to the front and rear brakes.
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At higher pressures, the pressure transmitted to the rear brakes will be lower than to the front brakes to prevent premature rear wheel lock-up
and skid.
If hydraulic pressure is lost in the front brake system, rear brake system hydraulic pressure moves the brake warning switch piston and opens a
bypass in the proportioning unit allowing full rear brake hydraulic pressure.
