ASE A4 Suspension and SteeringSteering System Diagnosis and RepairMedium
A customer complains of a noticeable vibration felt through the steering wheel that is worse during braking, but also present to a lesser degree during normal driving. The vibration intensity increases with vehicle speed. What is the MOST likely cause of this condition?
- AWorn or warped brake rotors.
- BAn unbalanced tire.
- CA loose steering rack mounting bushing.
- DA faulty power steering pressure sensor.
Show answer & explanationAnswer & explanation
Correct answer: A. Worn or warped brake rotors.
Vibration through the steering wheel that is worse during braking points strongly to worn or warped brake rotors. The lesser vibration during normal driving could be due to the rotors being out of balance or slightly warped even when not actively braking.
Why the other options are wrong
- B. An unbalanced tire would cause vibration primarily at speed, but not specifically worsen during braking.
- C. A loose steering rack bushing would typically cause clunking or vague steering, not a speed-sensitive vibration that worsens with braking.
- D. A faulty power steering pressure sensor would affect assist, not cause a mechanical vibration felt through the steering wheel.
Brake Rotor Warpage/Runout
Excessive lateral runout or warpage of brake rotors causes pulsation or vibration felt through the brake pedal and/or steering wheel, especially during braking.
- Primary symptom is vibration/pulsation during braking.
- Can cause minor vibration at speed even when not braking.
- Often exacerbated by heat from heavy braking.
Memory trick: Brake vibration means check the rotors.