After performing an alignment, a technician notices that the front left included angle is 10.0 degrees and the front right included angle is 12.0 degrees. The specification for included angle is 11.0 degrees +/- 0.5 degrees. This discrepancy, with other angles in spec, most accurately points to a problem with which component?
- AA worn or damaged ball joint on the right side.
- BA worn or damaged tie rod end on the left side.
- CIncorrect camber on the left side.
- DA bent steering knuckle on the right side.
Show answer & explanationAnswer & explanation
Correct answer: D. A bent steering knuckle on the right side.
Included angle is the sum of SAI and camber. Since SAI is a non-adjustable fixed angle and camber is adjustable (and implied to be in spec if 'other angles are in spec' or can be set), a significant difference in included angle between sides usually indicates a bent steering knuckle. The steering knuckle dictates the SAI, and if it's bent, it will alter the SAI and thus the included angle, even if camber is adjusted correctly.
Why the other options are wrong
- A. Worn ball joints mostly affect camber and toe, not typically creating a large included angle split unless severely damaged and affecting SAI.
- B. Worn tie rod ends primarily affect toe, not included angle directly.
- C. If camber was incorrect on the left side, it would directly affect the left included angle. However, the question states 'other angles in spec', implying camber is either in spec or adjustable to be in spec. The *split* in included angle, with camber potentially corrected, points to SAI.
Included Angle Diagnosis
Included angle is the sum of SAI and camber. A difference in included angle between sides, especially when camber is set correctly, indicates a bent steering knuckle or strut affecting SAI.
- Included Angle = SAI + Camber.
- SAI is fixed by design, camber is adjustable.
- Split IA often means bent knuckle/strut affecting SAI.
- Useful for diagnosing damage post-impact.
Memory trick: Included Angle's sum, if split, means the knuckle took a hit.