ASE A4 Suspension and SteeringWheel Alignment Diagnosis, Adjustment, and RepairHard
A technician is performing a four-wheel alignment on a vehicle with a solid rear axle. The alignment machine shows the rear total toe is -0.15 degrees and the rear thrust angle is -0.2 degrees. The specification for both is 0.0 +/- 0.1 degrees. What is the MOST appropriate next step?
- ACheck for bent axle housing or worn axle locating components.
- BAdjust the rear toe by modifying the individual toe settings on each rear wheel.
- CAdjust the front toe to compensate for the rear thrust angle.
- DInform the customer that a solid axle cannot be adjusted and no repair is possible.
Show answer & explanationAnswer & explanation
Correct answer: A. Check for bent axle housing or worn axle locating components.
On a vehicle with a solid rear axle, toe and thrust angle are generally non-adjustable. If these angles are out of specification, it typically indicates damage to the axle housing itself (bent) or worn/damaged components that locate the axle (e.g., control arm bushings, leaf springs, mounting points). These components must be inspected and replaced/repaired.
Why the other options are wrong
- B. Individual toe adjustment is not possible on a solid rear axle; the wheels move as a unit.
- C. Adjusting front toe is a compensation that does not fix the underlying rear axle issue and can lead to other handling problems and tire wear.
- D. While the angles themselves may not be directly adjustable, the cause (bent axle, worn bushings) is repairable by replacing components.
Solid Rear Axle Alignment Discrepancies
Out-of-specification toe or thrust angle on a solid rear axle usually indicates a bent axle housing or worn/damaged axle locating components, as these angles are typically non-adjustable.
- Toe and thrust are fixed on solid axles.
- Discrepancies mean damage or wear.
- Requires component repair/replacement, not adjustment.
Memory trick: Solid axles don't adjust; they bend or break.