Height Sensing Brake Proportioning Valve - Setting
Number: 84-120Section: 5 (V)
Date: April, 1984
Subject: HEIGHT SENSING BRAKE PROPORTIONING VALVE SETTING PROCEDURE
Model and Year: 1984 "C-K-G" 20-30 SERIES TRUCKS
TO: ALL CHEVROLET DEALERS
This bulletin is being published to provide the proper procedure to be followed in setting the height sensing brake proportioning valve on applicable vehicles.
This procedure must be followed whenever an existing valve and/or the linkage is disassembled or removed to insure proper valve operation.
1. Raise vehicle, axle must be allowed to hang free (no load condition).
Figure No. 1 - Lever Assembly:
2. Remove nut and disengage lever assembly from valve shaft (Figure #1).
3. Select appropriate plastic adjustment gauge shown in chart below that is available from WDDGM:
ADJUSTMENT GAUGE USAGE
P/N Code Color Vehicle Combination
14061394 A Green "C/K" 30 With G52
14061395 B Black C30 Less G52
C20 All K20903 G31305/06 With LE3/LS9
14061396 C Blue K30 Less G52
K20906 G31305/06 With LL4/LT9
(RPO G52: Extra Capacity Rear Spring)
Figure No. 2 - Plastic Adjustment Gauge:
4. Rotate valve shaft to permit installation of plastic adjustment gauge. Center "D" shaped hole of gauge must seat over "D" shape of the valve shaft and gauge tang must be positioned in valve mounting hole (Figure #2).
5. Reinstall lever assembly to the valve shaft utilizing a "C" clamp or channel lock pliers to seat lever nylon bushing to serrations on the valve shaft.
NOTICE: DO NOT DRIVE THE LEVER ONTO THE SHAFT USING ATTACHING NUT. DOING SO MAY RESULT IN IMPROPER VALVE SETTING.
6. Reinstall valve shaft nut and torque to 8-11 N-m (70-98 in.lbs.).
Figure No. 3 - Gauge Tang:
7. Cut gauge tang from body of the adjustment gauge to allow the valve assembly to rotate freely (Figure #3).
8. Lower vehicle and test brakes.