Height-Sensing Proportioning Valve
NOTE:
If front wheel lock-up is experienced during braking when vehicle is near maximum GVWR, adjust height-sensing proportioning valve.
- Raise and support vehicle. Ensure rear axle is hanging free and valve is securely bolted to frame before height-sensing proportioning valve is adjusted. See Fig 1.
- Remove nut and lever assembly from valve. Rotate valve shaft to allow installation of plastic adjustment gauge No. GM 15592484. Seat "D" shaped center hole over valve shaft. Gauge must be positioned in valve mounting hole.
- Install lever assembly to valve shaft with a "C" clamp or locking pliers to seat lever nylon bushing on serrated valve shaft. DO NOT install lever using attaching nut. Doing so can result in improper valve adjustment.
- Install valve shaft nut and tighten to 80 INCH lbs. (9 N.m). Cut tang from body of adjustment gauge, and allow valve to rotate freely. Lower vehicle and test brakes.