Rear Auxiliary Spring - Slap Noise

91chevy03

GMC NUMBER: 90-3D-90(B)


GROUP: 3D Rear Suspension


DATE: December, 1990


CORPORATE


NUMBER: 063401R


SUBJECT: REAR AUXILIARY SPRING NOISE


MODELS: 1988-90 C2, C3, K3 TRUCKS (MODELS C20903, C/K30903 & R05 (DUAL REAR WHEELS) AND C/K30953 & R05) EQUIPPED WITH AUXILIARY REAR SPRINGS


THIS BULLETIN CANCELS AND REPLACES GMC TRUCK SERVICE BULLETIN 90-3D-90(A) DATED OCTOBER, 1990 TO RESTRICT INVOLVED TRUCKS TO MODELS C20903, C/K30903 & R05 AND C/K30953 & R05. ALL COPIES OF 90-3D-90(A) SHOULD BE DISCARDED.





Some 1988-90 C2, C3 and K3 trucks equipped with auxiliary rear springs may experience a noise from the rear spring area. This noise may be described as a slap sound and is caused when the auxiliary, or second stage springs, contact the spring stops. This condition can be repaired by replacing the existing spring stops and insulators with revised one piece spring stops. These revised spring stops feature insulators which are molded directly to the metal stop (Figure 1).

Figure 2-Rear Spring Stop, Front:

Figure 3-Rear Spring Stop, Rear:

INVOLVED VEHICLES:

All 1988-90 C2, C3 & K3 vehicles (models C20903, C/K30903 & R05 (dual rear wheels) and C/K30953 & R05) equipped with auxiliary rear springs. These involved vehicles can be identified from other C3 & K3 models by examining the rear auxiliary spring stops (Figures 2 & 3). If the design and bolt pattern do not match those shown in Figures 2 & 3 the truck is not involved and the part numbers listed cannot be installed on the truck. Vehicles built after the VIN breakpoints listed below are equipped with the revised stops.


Figure No. 1