Height Sensing Proportioning Valve

DESCRIPTION
The height sensing proportioning valve is used on 2500 model vehicles with RWAL. The valve is mounted to the left frame rail above the rear axle. The valve has an actuator lever connected by a link to the left lower shock bracket. The valve is turned on and off as the axle to frame height changes due to the load in the vehicle. A torsional clutch spring attached to the valve shaft and cam is used as an override feature. Once the valve is positioned during brake application, the spring prevents the valve from changing position in the event of an abrupt suspension movement such as going over a bump. During this instance the cam is held in position while the shaft is allowed to rotate.

CAUTION: Any modification to the suspension which would affect suspension height, also may affect braking performance. If the valve assembly is replaced for service, the lever must not be adjusted, it is preset at the factory. The Height Sensing Proportioning Valve is service as an assembly only.

OPERATION






The Height Sensing Proportioning Valve provides two different brake balance modes to the rear brake based on the vehicle load. This is accomplished by turning the valve on or off. When the vehicle is not loaded hydraulic pressure is reduced to the rear brakes after the split point. When the vehicle is carrying a full load the actuator lever moves up to change the valve setting. The valve now allows full hydraulic pressure to the rear brake. The valve contains a plunger, cam, torsional clutch spring and actuator shaft. This valve is used on all 2500 model 4x4 and 4x2 vehicles with RWAL.