Suspension - Choppy Ride Due to Front Shocks
90chevy09GMC NUMBER: 89-3C-131
GROUP: 3C Front Suspension
DATE: May, 1990
CORPORATE
NUMBER: 063301
SUBJECT: CHOPPY RIDE DUE TO OVER EXTENSION OF FRONT SHOCKS (NEW TORSION BAR ADJUSTER)
MODELS: 1988-1989 K1, K2, K3 TRUCKS WITH F60 (HEAVY DUTY FRONT SPRINGS)
A 1990 model torsion bar adjusting arm (Part # 15603963) is now available through GMSPO for 1988 and 1989 model trucks equipped with F-60 option that continue to damage front shocks, even after adjusting the torsion bar for the lowest front ride height. This new torsion bar adjusting arm will provide a lower front ride height, thus preventing over extension and damage to shocks. These adjusters will not change Gross Front Axle Weight Rating (GFAWR).
Figure 1 - Torsion Bar Adjuster Height:
Figure 2 - Torsion Bars and Support:
SERVICE PROCEDURE:
Removal Procedure For Torsion Bar Adjustment Assemblies On Both Torsion Bars (See Figures 1 And 2). Tool Required:
J 36202 - Torsion Bar Unloading Tool
1. Raise vehicle front and support with suitable safety stands.
2. Increase the tension on adjustment arm (186) using J 36202.
3. Remove adjustment bolt (184) and retaining plate (185).
4. Release tension on adjustment arm and move tool aside.
5. Slide torsion bars forward.
6. Remove the adjustment arms (186).
Replacement Procedure For New Torsion Bar Adjustment Assemblies On Both Torsion Bars (See Figures 1 And 2). Tool Required:
J 36202 - Torsion Bar Unloading Tool
1. Fit the new torsion bar adjusting arms (Part # 15603963) on the torsion bars.
2. Increase the tension on the torsion bar, using J 36202.
3. Install the retaining plate and the adjustment bolt.
4. Release the tension on the torsion bar until the load is taken up by the adjustment bolt.
5. Remove J 36202.
6. Lower the vehicle.
7. Reset "Z" height and front end alignment to the specifications listed at the end of this bulletin.
SERVICE PARTS INFORMATION:
WARRANTY INFORMATION:
For repairs under warranty use:
Labor Operation: T8130 Replace both torsion bar adjuster arms, set "Z" height, and check front wheel alignment.
Labor Time: .9 hr.
Add: To Align Front Wheels
- K Trucks without cam kits previously installed. 1.2 hrs.
- K Trucks with cam kits previously installed. .6 hrs
NOTE: Labor operation is coded to base vehicle coverage in the warranty system.
SERVICE SPECIFICATIONS
After installing these adjusters the Z height setting and alignment specifications should be reset to the revised 1990 specifications listed below:
Document shown below should be produced locally and provided to the owners of vehicles modified by this repair procedure.