Radius arms

Grinding sound when going round SHARP left hand corners?

It's worth taking a close look at the radius arm bearings. No play doesn't *always* mean they're not knackered.

I've had ones where the bearings have worn away so badly that the debris have literally "back-filled" on them, ending up with an off-centre, semi-seized, but playless shaft. (This is normally only the result of years of neglect though)

Radius Arm Bearing Renewal

The method below requires only one special tool - an adjustable parallel hand reamer, size 0.8125 to 0.8130", 26/32", 20.63 to 20.65mm (per BMC AKD4061A updated 19.02.2004)

A drift is constructed using the old shaft and a thick flat washer that is cut in approximately halves. The washer diameter is approximately 24.7 mm after being cut in half.

Note that in the procedure, the term "trailing arm" is used. This is another term for the radius arm.

1. Remove trailing arm from the vehicle. See other references for this procedure

2. Remove shaft from housing to leave the bush and needle roller bearing exposed

3. Mount the arm in a vice etc so that a hacksaw blade can be used to saw into the bush

4. Locate the join in the bush and make a cut in the bush roughly parallel with the join. Cut deep enough and far enough away from the join to enable the use of a small cold chisel to remove a section of the bush. Do not cut into the trailing arm. This is a fiddly job but is probably the easiest way without a special bush removing tool

5. Remove the rest of the bush

6. Drift in new bush

7. Use the adjustable parallel hand reamer to enlarge the hole to fit the new shaft. Increase the reamer’s size by very small increments and retry the shaft each time, as it is very easy to make the hole too big. Again, a very fiddly job but vital to get correct size otherwise shaft will be sloppy in the new bush

8. Remove old needle roller bearing. Use the old shaft as a basis of a drift with a thick flat washer that has been cut in half. The two halves are fitted in behind the bearing. By having it cut into two pieces and the central hole large enough for the threaded section of the old shaft to pass through it enables the bearing to be pushed out. Maybe a bearing extractor could be used?

9. Remove the old grease tube from inside the arm. This is a tapered item that can be removed from the roller bearing end

10. Remove old grease from the arm. Often grease has gone past the tube and filled the hollow parts of the arm. Remove as much as is required to get rid of swarf and any water contaminated grease

11. Slide in the new grease tube

12. Drift in the new needle roller bearing

13. Insert the new shaft

14. Refit to vehicle and grease well

15. Reconnect brake backing plate, brake lines etc and bleed brakes

Original article by Richard Penalurick