Ball Joints (Greaseable) - Added Service Requirements: Overview
91chevy21
Number: 90-392A-3C (REVISED)
Section: 3C
Date: AUGUST 1991
Corporate Bulletin No.: SPECIAL
Subject: SPECIAL POLICY ADJUSTMENT GREASEABLE UPPER AND LOWER CONTROL ARM BALL JOINTS AND FRONT END ALIGNMENT PARTS KIT
Model and Year: 1988-90 C/K TRUCKS
TO: ALL CHEVROLET DEALERS
THIS BULLETIN SUPERSEDES CHEVROLET DEALER SERVICE BULLETIN 90-392-3C DATED DECEMBER, 1990, TO REVISE THE SERVICE PROCEDURE AND CLAIMS INFORMATION SECTIONS FOR ALL REPAIRS COMPLETED ON OR AFTER AUGUST 5, 1991.
REVISIONS TO THIS BULLETIN INCLUDE ADDITION OF A REQUIREMENT TO CHECK THE CONDITION OF 1990 MODEL YEAR C/K TRUCK MAINTENANCE FREE BALL JOINTS BEFORE REPLACEMENT, ELIMINATION OF CASTER/CAMBER ALIGNMENT AND THE ADDITION OF TOE-IN ALIGNMENT.
BALL JOINTS:
A contaminated 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.
Notice: Any vehicle equipped with greaseable ball joints are not to be replaced as a part of this special policy.
1988-89:
Some of the maintenance-free front suspension ball joints used on 1988 and 1989 model C/K trucks have experienced contamination.
1990:
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. These maintenance-free front suspension ball joints, used in the 1990 model C/K trucks, incorporated two significant changes that greatly reduce the possibility of contamination.
- An enhancement was made at the neck of the ball joint by changing the material of seal insert to glassfilled 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 truck 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 PROCEDURE INCLUDED IN THIS BULLETIN INDICATES OVER 1 MM (0.040 INCH) OF VERTICAL LOOSENESS. THIS DIMENSION IS TO BE RECORDED ON THE REPAIR ORDER.
Greaseable ball joints were also used in 1990 model year production as follows since:
- start of production on C truck front suspension lower control arms;
- interim production on C truck front suspension upper control arms; and
- interim production on 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).
Figure 1:
Replacement Ball Joints:
Greaseable ball joints should be used as replacements for contaminated maintenance-free ball joints. Since it is important to lubricate the greaseable ball joint, customers must be given the information slip, shown in figure 1 below, which explains the greaseable ball joint maintenance requirements. This slip is packaged in each service ball joint kit.
FRONT WHEEL CASTER/CAMBER ALIGNMENT PARTS KIT:
The 1988-90 C/K trucks, incorporate a front suspension feature designed to improve the vehicle's ability to maintain front wheel caster/camber alignment. The front wheel alignment set by the assembly plant will not change and should not need adjustment except in cases where accident or road hazard damage has occurred. Through the listed VIN breakpoints, in customer pay situations, if caster/camber alignment was performed the customer was also charged for the required alignment parts kit. Due to the cost of the parts kit, the charge for a wheel alignment would not be competitive in today's marketplace. In view of this, Chevrolet Motor Division has issued a special policy which covers the cost of the caster/camber alignment parts kit, but not the installation cost. This kit is included in vehicles currently being produced.