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The idler arm is a small but important part of the R107‘s steering linkage. When its bushings wear, the steering feels vague, the car wanders and the tires wear unevenly.
What the idler arm does
The R107 uses a steering box with a linkage: the pitman arm on the box, a center link, tie rods, and an idler arm on the opposite side that supports the other end of the center link. The idler arm pivots on bushings in a bracket bolted to the body or subframe.
Symptoms
- Loose, vague steering around center
- Wandering on the highway
- A clunk when turning the wheel back and forth
- Uneven tire wear on the front
Inspection
- With the car on the ground or the wheels on ramps, have a helper rock the steering wheel back and forth gently.
- Watch the idler arm: it should pivot with no up-and-down movement.
- Lift the end of the idler arm with a pry bar: noticeable vertical play means worn bushings.
- Check for cracked or torn rubber.
Bushing kit
Idler arm bushing kits are inexpensive. Some owners prefer to replace the whole idler arm assembly if the pin or bracket is worn.
Replacement
- Raise and support the car safely.
- Separate the center link from the idler arm with a ball joint separator.
- Remove the idler arm and its bushings from the bracket.
- Fit the new bushings, sometimes requiring a press or careful tapping.
- Reassemble and tighten the nuts to spec.
Alignment after
Check toe after replacing steering linkage parts. Worn idler bushings often hide other worn parts, so check tie rod ends and the center link at the same time.
Quick answers
- Is steering play always the idler arm? No. Check the steering coupler and box adjustment too; see steering play.
- Can I do it without a press? On many cars yes, with a socket and a bench vise, but a press makes it easier.
- Should I replace the steering damper too? If it is weak or leaking, yes; it is cheap and helps stability.
- How long does an idler arm bushing last? It depends on use; inspect it whenever the front end is checked.
- Can a worn idler arm cause tire wear? Yes, it lets toe change as the car moves.
