TORQUE STEER TO THE RIGHT DIAGNOSIS ASSISTANCE

Model and Year FRONT-WHEEL DRIVE CARS

TO: ALL CHEVROLET DEALERS

A degree of torque steer to the right may normally be experienced during heavy throttle application on some front-wheel-drive vehicles. This is due to the right drive axle being longer than the left axle and associated difference in axle angle.

The axle difference results in more torque toe-in effect to the left front wheel, especially on manual transmission-equipped cars. This condition may be noticed when accelerated from a standing start and on some models at lower speeds. A simple measurement to determine the degree of torque steer is to place a small piece of tape at the top center of the steering wheel. Drive the car and note the inches of steering wheel deflection required to steer the car straight under heavy throttle acceleration. A comparison of like cars will then determine if a particular car has a greater than normal degree of torque steer. The following factors may cause torque steer to be more apparent on a particular car:

1. A slightly smaller diameter tire on the right front will increase a right torque lead. Inspect front tires for difference in brand, construction, or size. If the tires appear similar, change the front tires side to side and retest the car. Tire and wheel assemblies have the most significant effect on torque steer correction.

2. Large difference in right and left front tire pressure.

3. Any looseness in control arm inner bushings, steering linkage, or steering gear mounting which permits a front wheel to pull forward and toe-in under torque more than the opposite side. A loose suspension component may also result in an opposite lead on deceleration.

4. High front suspension height which would increase drive axle angle.

5. Binding or tight drive axle joint. A tight joint or high-suspension height may also exhibit a wobble condition between 15 mph and 30 mph.

6. Incorrect, worn, or loose engine mounts causing adverse drive axle angles. The less prominent the left drive axle angle is the less the right torque steer effect will be. However, shimming the engine mounts or cradle has not resulted in more than a minor improvement of torque steer.

The following conditions affect car steering pleasability and/or a constant right or left lead independent of torque steer causes. However, the exis- tence of one or more of these conditions may compound a torque steer com- plaint:

1. Incorrect front-wheel alignment or a rear-wheel alignment condition which would cause the car not to track straight.

2. Cradle misalignment or side rail support misalignment. Section 2A and 3A of the applicable 1986 Service Manual lists measurement points to determine proper cradle and underbody alignment.

NOTE: A difference in the front wheel to rear wheel measurement compared side to side may indicate a "dog track" condition or one front wheel ahead of the other due to cradle misalignment. A substantial caster difference is an indication of cradle misalignment. Minor caster difference may be corrected by slotting the tower strut mounting holes. Caster should be equal. Camber may be biased slightly to offset a lead condition.

3. Front suspension damage, such as a bent strut.

4. Tire residual aligning torque. Exchange tires with a known good car to diagnose.

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.