ASE A4 Suspension and SteeringSteering System Diagnosis and RepairHard
A customer reports a grinding noise when turning the steering wheel, particularly at low speeds, on a vehicle equipped with a rack-and-pinion steering system. The noise sounds metallic and is felt slightly through the steering wheel. Power steering fluid level is correct and clean, and the power steering pump is quiet. What is the MOST likely cause?
- AA worn power steering pump.
- BA loose steering rack mounting bushing.
- CA binding steering column U-joint.
- DInternal wear within the rack-and-pinion gear set.
Show answer & explanationAnswer & explanation
Correct answer: D. Internal wear within the rack-and-pinion gear set.
A metallic grinding noise heard and felt through the steering wheel, especially at low speeds and with a quiet pump, strongly indicates internal mechanical wear within the rack-and-pinion gear set itself. This could be due to worn pinion bearings, rack teeth, or a damaged rack bushing.
Why the other options are wrong
- A. A worn pump usually causes a whine or groan, and the pump is described as quiet.
- B. A loose mounting bushing would typically cause clunking, not a grinding noise felt through the steering wheel during turns.
- C. A binding U-joint typically causes a clunk or a stiff spot, not a grinding noise felt through the wheel.
Rack-and-Pinion Internal Wear
Wear or damage to the internal components of a rack-and-pinion steering gear, such as the pinion bearings, rack teeth, or internal bushings, resulting in grinding noises and/or excessive play.
- Causes metallic grinding noise, especially when turning.
- Noise is often felt through the steering wheel.
- Requires replacement or rebuild of the steering rack.
Memory trick: Grinding gear is an internal fear.