SERVICE MANUAL UPDATE SEC. 3D REAR SUSPENSION DIAGNOSIS

SUBJECT: SERVICE MANUAL UPDATE - REAR SUSPENSION - REPLACE PAGE 3D-1

MODELS/YEARS: 1991 CUTLASS CIERA AND CUTLASS CRUISER

The illustration on the back of this bulletin replaces page 3D-1 of the 1991 Cutlass Ceira and Cutlass Cruiser Service Manual.

Please mark a reference to this bulletin in your copy(s) of that manual.

SECTION 3D REAR SUSPENSION

NOTICE: When fasteners are removed, always reinstall them at the same location from which they were removed. If a fastener needs to be replaced, use the correct part number fastener for that application. If the correct part number fastener is not available, a fastener of equal size and strength (or stronger) may be used. Fasteners that are not reused, and those requiring thread locking compound will be called out. The correct torque value must be used when installing fasteners that require it. If the above conditions are not followed, parts or system damage could result.

CONTENTS

Diagnosis.......................................... Section 3 General Description .................................... 3D-1 On-Vehicle Service ..................................... 3D-1 Ride Complaints ..................................... 3D-1 Excessive Friction Check.............................. 3D-1 Shock Absorber........................................ 3D-2 Upper Shock Absorber Mount............................ 3D-2 Track Bar............................................. 3D-2 Brace (Wagon)......................................... 3D-3 Spring and Insulators ................................ 3D-4 Control Arm Bushings ................................. 3D-4 Rear Axle Assembly ................................... 3D-5 Hub and Bearing Assembly ............................. 3D-6 Wheel Bolt ........................................... 3D-6 Specifications ......................................... 3D-8 Fastener Torque Specifications........................ 3D-8 Special Tools........................................... 3D-8

GENERAL DESCRIPTION

The rear suspension consists of a rear axle assembly, two coil springs, two shock absorbers, track bar and a track bar brace (Figure 1). The rear axle assembly is the trailing arm type of design. Two control arms, welded to the axle housing are used to mount the axle assembly to the body. The control arms, with the track bar, track bar brace and shock absorbers, maintain the relationship of the rear axle to the body, oppose torque reaction on acceleration and braking and provide for best handling. A non-serviceable stabilizer shaft, welded to the inside of the axle housing, is an integral part of the rear axle assemblies. The rear coil springs are retained between a seat on the underbody and a seat welded to rear axle. A rubber insulator is used to isolate the coil spring from the underbody seat and lower spring seat. The track bar is a single unit with non-replaceable bushings at either end. It attaches to the axle assembly on one end and to the underbody at the other end. The track bar controls the side movement of the rear axle assembly.

ON-VEHICLE SERVICE

The brake system should be carefully inspected for damage if improper positioning, incorrect assembly or failure of any component in the area of brake pipes, hoses or cylinders is observed. Immediately correct damage as required. Components that could damage the brake system due to improper positioning, incorrect assembly or failure include the exhaust system, stabilizer shaft and control arms.

RIDE COMPLAINTS

If complaints of hard ride are encountered, the first items to investigate are tire pressure, trim height and shock absorber condition. If these are correct, the amount of friction in the rear suspension should be checked. For additional diagnosis, refer to DIAGNOSIS (SECTION 3).

EXCESSIVE FRICTION CHECK

The procedure for checking excessive friction in the rear suspension is as follows:

1. With the aid of a helper, lift up on the rear bumper and raise vehicle as high as possible. Slowly release the bumper and allow the vehicle to assume normal trim height.

2. Measure distance from floor to center of bumper.

3. Push down on bumper, release slowly and allow vehicle to assume normal trim height.

4. Measure distance from floor to center of bumper.

The difference between the two measurements should be less than 12.7 mm (1/2 in.). If the difference exceeds this limit, inspect the control arms and shocks for damage or wear.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.