K 2500 Truck 4WD V8-379 6.2L DSL VIN C FI (1989)
Technical Service Bulletin # 903C60B
Campaign - Ball Joints/Alignment
3C Front Suspension
SPECIAL POLICY ADJUSTMENT - GREASEABLE UPPER & LOWER CONTROL ARM BALL JOINTS AND FRONT END
ALIGNMENT PARTS KIT
1988-90 C/K TRUCKS
THIS BULLETIN CANCELS AND REPLACES GMC TRUCK SERVICE BULLETIN 90-3C-60(A) DATED DECEMBER, 1990 TO REVISE THE
SERVICE PROCEDURE AND THE LABOR TIMES. ALL COPIES OF 90-3C-60(A) SHOULD BE DISCARDED.
REVISIONS TO THIS BULLETIN INCLUDE ADDITION OF A REQUIREMENT TO CHECK THE CONDITION OF 1990 MODEL YEAR C/K
MAINTENANCE-FREE BALL JOINTS BEFORE REPLACEMENT, ELIMINATION OF CASTER/CAMBER ALIGNMENT AND ADDITION OF
A contaminated front suspension ball joint can cause squeaking while turning and/or require more frequent steering input while driving down the road.
Contamination could also cause a ball joint to wear out and eventually to separate. 1988-1989 Some of the maintenance-free front suspension ball joints
used on 1988 and 1989 model C/K trucks have experienced contamination.
Later design maintenance-free ball joints were used in early 1990 model C truck front suspension upper control arms and K truck front suspension upper
and lower control arms. Those maintenance-free front suspension ball joints used in the 1990 model C/K trucks incorporated two significant design
changes that greatly reduce the possibility of contamination.
An enhancement was made at the neck of the ball stud by changing the material of the seal insert to glass-filled nylon for greater stiffness and less
shrinkage when cold. In addition, the composition of the seal was changed to make it more flexible in cold weather.
Since the first publication of the Special Policy Adjustment Bulletin, stringent lab testing, proving ground durability tests and a fleet field test have
demonstrated the durability of the 1990 model C/K maintenance-free front suspension ball joints.
Therefore to determine whether a customer complaint is attributable to contamination of a maintenance-free ball joint on a 1990 model truck, do not
replace any such ball joint unless the ball joint wear check included in this bulletin indicates over 1 mm (0.040 inch) of lash.
Greaseable ball joints were also used in 1990 model year production as follows since:
start of production on the C truck front suspension lower control arms;
interim production on the C truck front suspension upper control arms; and
interim production on the K truck front suspension upper and lower control arms.
The greaseable style ball joint incorporates a zerk fitting to facilitate maintenance and is designed to allow grease to purge at the interface of the rubber
dust cover and the ball joint shell (or socket).