C 2500 3/4 Ton Pickup 2WD V8-379 6.2L DSL VIN J FI (1984)
Brake Proportioning/Combination Valve: All Technical Service Bulletins
Height Sensing Brake Proportioning Valve - Adjustment
NUMBER:
86-B-93
GROUP:
5A - Brakes Hydraulic
DATE:
June, 1986
SUBJECT:
HEIGHT SENSING BRAKE PROPORTIONING VALVE ADJUSTMENT PROCEDURE
MODELS:
1984-1985 C/K 25 SUBURBANS
THIS BULLETIN CANCELS AND SUPERSEDES 86-B-2 (September, 1985), ALL COPIES OF WHICH SHOULD BE DESTROYED.
The brake balance on 1984-1985 C/K 25 Suburbans can be adjusted in order to enhance rear braking performance under lightly loaded vehicle
conditions. In order to change brake balance, it will be necessary to adjust the height sensing brake proportioning valve. In addition, burnishing the
brakes following the procedure below may be beneficial on some vehicles.
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).
Disengage Lever Assembly
^
Remove nut and disengage lever assembly from valve shaft (Figure No. 1).
Gauge Tang Position
^
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 No. 2).
^
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.
NOTE:
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 in.lbs.).