ASE A4 Suspension and SteeringSteering System Diagnosis and RepairHard
A technician is performing a road test on a vehicle with a complaint of a 'loose' steering feel and excessive play in the steering wheel. During the inspection, the technician observes that when the steering wheel is turned, the steering shaft rotates, but there is a noticeable delay and slack before the input pinion on the rack-and-pinion assembly begins to move. Which of the following is the MOST likely cause?
- AA worn upper steering column bearing.
- BA loose or worn steering column universal joint.
- CExcessive backlash in the steering rack's internal gears.
- DDeteriorated steering rack mounting bushings.
Show answer & explanationAnswer & explanation
Correct answer: B. A loose or worn steering column universal joint.
If the steering shaft rotates but there's a delay before the rack's input pinion moves, it indicates a loss of direct connection within the steering shaft itself. A loose or worn steering column universal joint (U-joint) is designed to allow articulation but must transmit rotational force precisely. If it's worn, it will have excessive play, causing slack and delay in steering input transmission.
Why the other options are wrong
- A. A worn upper steering column bearing would cause a wobble or play in the steering wheel itself, not a delay in transmitting movement from the shaft to the rack.
- C. Excessive backlash in the steering rack's internal gears would mean the input pinion moves, but the rack bar itself has play before moving the wheels, not a delay between the shaft and the pinion.
- D. Deteriorated steering rack mounting bushings would allow the entire rack to shift, causing a vague feel and wander, not a delay between the steering shaft and the rack's input pinion.
Steering U-Joint Play
Excessive play in a steering column universal joint (U-joint) causes a 'loose' steering feel, slack, and a noticeable delay between steering wheel rotation and the movement of the steering rack's input pinion.
- Connects sections of steering shaft.
- Allows for angular movement.
- Wear causes lost motion and delay in steering.
Memory trick: Shaft moves, pinion waits? U-joint's loose, mate!