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Home >> GMC >> 1981 >> Magnavan Standard Trans >> Repair and Diagnosis >> Brakes >> Brakes Control Systems >> Brake Systems - Hydraulic System Control Valves >> Operation >> Proportioning Valve
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Proportioning Valve

Valve operates by restricting, at a given ratio, hydraulic pressure to rear brakes when system hydraulic pressure reaches a certain point. This improves front-to-rear brake balance at high speed braking, when a percentage of rear weight is transferred to front wheels. Valve reduces rear brake K pressure, and delays rear wheel skid. On light brake application, valve allows full hydraulic pressure to rear brakes.