Friday, 2 October 2015

E60: Replacing Rear Rose-Bushes / Lower Ball-Joints

These are the main joint where the rear wheel-hubs attach to the trailing-arms and are a pretty common replacement on high mileage 5 and 7 series. They were the advisories I got on the MOT in February, so thought I should get them done before the nice weather ends.

DIFFICULTY - 6/10 This is not a long or complicated job, but is quite labour intensive.

** YOU WILL NEED: A dedicated removal / installation tool. These are available on eBay [here] for just under £40 and work for all modern 5, 6, 7, X5 and X6 rose-bushes. These are all copies of the BMW special tools listed here on TIS.

The rose-bush is item 2 in the diagram.

1. Lift car, remove rear wheel, support on axle-stand.

2. Unbolt the anti-roll bar link from the trailing-arm using an 18mm open/ring spanner on the nut from underneath, while holding the stud from turning using a T40 Torx socket through the centre of the spanner.

3. Loosen the long bolt that holds the trailing-arm to the wheel hub [5] using a 24mm wrench on the nut and an 18mm wrench on the bolt head. [A long breaker-bar is advisable on the nut.]

4. Loosen off the eccentric-bolt on the trailing-arm [11] using an 18mm wrench on the bolt head and a 21mm wrench on the nut. [Be careful not to turn the bolt and alter the alignment as it's hard to get back.]

5. Loosen off the other bolt on the trailing arm [9] using an 18mm wrench on both the nut and bolt head.

6. Fully remove the 24mm nut [6] and long bolt [5] from the wheel-hub. [The bolt will likely need knocking out with a drift.]

7. Remove the bolt holding the push-rod to the wheel-hub [7] using an 18mm wrench.

7a. (O/S trailing-arm only) - Disconnect the suspension-angle sensor from the trailing-arm using a 10mm wrench and 10mm open-end spanner.

8. Lever the trailing arm down so it is clear of the wheel-hub and the push-rod [4] can be removed.

9. Remove the retaining-ring [3] from the rear face of the rose-bush. [It will likely be well seized in place and need splitting with a grinder / cut-off tool before knocking out in two pieces.]

10. Set up the removal-tool either side of the rose-bush with the largest mandrel on the receiving side and the smallest mandrel on the pushing side, ensuring the pushing side is completely flush to the rose-bush face. [Some of the rose-bush rubber boot may need cutting off to ensure this.]

11. Tighten up the removal-tool using a 19mm wrench on either side until the bush pops out of the wheel-hub. [Rotating the receiving mandrel round so the notched area can be viewed from underneath shows the progress of the bush coming out.] [The bush may well need some heat treatment if it is seized, or you can have a go at splitting it if you are brave enough.]

12. Place the new rose-bush into the hub, ensuring it is straight to the collar and will go in evenly. [The bush always slots it from front to rear, with the retaining ring on the rear face.]

13. Set up the removal-tool on the new rose-bush with the largest mandrel on the receiving side again and the mid-sized mandrel on the pushing side. [The notched side of the receiving mandrel will need rotating so it fits flush past the back of the brake disc. This is essential to keep the threaded-bar / bush straight.]

14. Tighten up the removal-tool with two 19mm wrenches until the bush is fully seated in the collar. [The bush should slide in pretty easily, if it resists then it is not going in straight. A small amount of copper grease can be rubbed round the bush to aid it, but be very sparing.]

15. Fit the new retaining-ring to the rear face of the rose-bush.

16. Refit the push-rod and trailing arm etc. as a reversal of steps 8 to 1.

** For correct re-alignment of suspension geometry see this post. **

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