Height Sensing Proportioning Valve
- Premature front wheel lock-up created during near maximum Gross Vehicle Weight Rating (GVWR) with lower than average application may be caused by incorrect adjustment.
- To adjust height sensing proportioning valve, raise vehicle using hoist allowing rear suspension to hang free. Ensure that rear suspension is not contacting hoist.
- Remove nut from valve shaft and remove lever assembly. See Fig 1. Adjustment gauge must be installed on valve shaft. Different adjustment gauges are used pertaining to vehicle applications. See current service parts listing for proper adjustment gauge to be used.
- Once proper adjustment gauge is determined, rotate valve shaft to allow installation of adjustment gauge. Adjustment gauge center hole must seat on the "D" shape of the valve shaft, and the tang must engage in the mounting hole.
- Install lever assembly on valve shaft. Push the plastic bushing and clip assembly over the valve shaft serrations. A "C" clamp may be used to aid in the installation of lever assembly. Serrations on the valve shaft will fully engage the plastic bushing when lever assembly is fully installed.CAUTION: DO NOT force lever assembly on valve shaft using the retaining nut. Installation of lever assembly using the retaining nut may result in improper valve setting.
- Once lever assembly is properly seated on valve shaft, install retaining nut and tighten to 70-98 INCH lbs. (8-11 N.m). Break tang on adjustment gauge to allow valve assembly to rotate freely. Test brake operation.