K 1500 Truck 4WD V6-262 4.3L (1991)
Brake Proportioning/Combination Valve: Technical Service Bulletins
Height Sensing Brake Proportioning Valve - Adjustment
Number: 91-190-5
Section: 5
Date: February 1991
Corporate Bulletin No.: 065025
Subject:
HEIGHT SENSING BRAKE PROPORTIONING VALVE ADJUSTMENT
Model and Year:
1991 C3 3500 HD
The following service procedure describes how to adjust the height sensing brake proportioning valve on 1991 C3500 HD trucks.
The procedure should be used whenever the height sensing linkage has been disconnected from the height sensing brake proportioning valve during
routine service. This adjustment is made during assembly on all 1991 C3500 HD trucks.
Figure 1
SERVICE PROCEDURE:
Note:
Always make sure that the brakes are operational after performing brake work and before returning the vehicle to service.
^
Raise vehicle, axle must be allowed to hang free (no load condition).
^
Remove nut and disengage lever assembly from valve shaft (Figure 1).
^
Rotate valve shaft to permit installation of plastic adjustment gage. Center "D" shaped hole of gage must seat over "D" shape of the valve shaft
and gage tang must be positioned in valve mounting hole (Figure 1).
^
Reinstall lever assembly to the valve shaft utilizing a "C" clamp or channel lock pliers to seat lever nylon bushing to serration on the valve shaft.
Important:
Do not drive the lever onto the shaft using the attaching nut. Doing so may result in improper valve setting.
^
Reinstall valve shaft nut and torque to 8 - 11 N-m (70 - 98 lbs.in.)
^
Cut gage tang from body of the adjustment gage to allow the valve assembly to rotate freely.
^
Lower vehicle and test brakes.
