C/V Boot - Contacts Front Shock: Overview
91chevy18
Number: 91-311-4C
Section: 4C
Date: MAY 1991
Corporate Bulletin No.: 164301R
Subject: FRONT AXLE INNER C/V BOOT CONTACTS FRONT SHOCK
Model and Year: 1985-91 T TRUCKS
Some 1985-91 T trucks may experience a condition of the front axle tripot seals (commonly referred to as the inner C/V boots) contacting the front shock absorbers. This contact usually occurs during suspension operation and may be evidenced as torn seals, premature wear on the outer edges of the seal convolutes or grooves worn into the body of the shock absorber.
This condition can be relieved by correcting problems with shock absorber or axle installation and installing smaller profile tripot seals.
VEHICLES INVOLVED:
1985-91 T trucks.
SERVICE PROCEDURE:
The following items should be checked and verified to provide the greatest amount of clearance for the tripot seals.
- The shock absorbers are installed correctly with the fluid reservoir on the bottom and the shield on the top.
- If aftermarket shock absorbers have been installed, their diameter must measure 50.4 mm (1.98") or less.
- The output shaft retaining ring is in place. To check, pull outward on the output shaft. Outward movement should measure 5 mm (.200") or less.
IMPORTANT: DO NOT cut or relocate shock absorber mounting brackets.
If the contact between the tripot joint and shock absorber is occurring on the passenger side of the vehicle, the axle assembly may be shifted in the frame too far toward the passenger side. To correct this condition the procedure below should be followed:
Figure 16 - Carrier Assembly Installation:
Figure 16
1. Loosen bolts (90) attaching the axle tube bracket (5) to the frame bracket (6).
2. Tighten nuts (94) to 75 N-m (55 lbs.ft.). This should cause the axle assembly to move toward the driver's side approximately 1/8" to 1/4". If the axle does not move it may be pried toward the driver's side with a bar. Position bar against the frame and the end of the shaft (1).
3. Tighten bolts (90) to 75 N-m (55 lbs.ft.).