
The front wheels aim or steer the vehicle. The rear wheelscontrol tracking. This tracking action relates to the thrustangle-(3). The thrust angle is the path that the rearwheels take. Ideally, the thrust angle is geometrically alignedwith the body centerline-(2).
In the illustration, toe-in is shown on the left rear wheel,moving the thrust line-(1) off center. The resultingdeviation from the centerline is the thrust angle.
If the thrust angle is not set properly the vehicle may“dog track”, the steering wheel may not becentered or it could be perceived as a bent axle. Thrust angle canbe checked during a wheel alignment.
Positive thrust angle means the thrust line is pointing tothe right hand side (RHS) of the vehicle.
Negative thrust angle means the thrust line is pointing tothe left hand side (LHS) of the vehicle.
If the thrust angle is out of specification, moving the axleto body relationship will change the thrust angle reading.
If the vehicle is out in the Positive (+) direction-movingthe RHS forward and/or LHS rearward will move the thrust angletowards zero degrees.
If the vehicle is out in the Negative (−)direction-moving the RHS rearward and/or LHS forward will move thethrust angle towards zero degrees.
Front Caster Adjustment Wheels
Tread Wear Indicators Description Wheels#04-00-89-015E: Warranty Administration - Required Operating Procedures (U.S. Only) - (Jun 20, 2013)
Subject:Warranty Administration – Required Operating Procedures (U.S. Only)Models: 2014 and Prior GM Cars and TrucksAttention: GM of Canada Service Agents are not authorized to utilize this service bulletin. GMof Canada Agents should reference the General Motors of Canada Limited Service Policie ...