Mot Failed!

[Zaphod]

Been to have my XM tested, nothing shocking to report but I'd like some advice from anyone that has had to do this!..

The front bush on the lower suspension arm has failed, (I had been wondering about the knocking noise I occasionally have been getting!) So they have to be changed. I see they push in from each side. I also need to do the CV Gaiter on that side as well along with a new tyre (killed by the dead bush it seems).
Any advice on these two problems?


Stewart

This post has been edited by Zaphod on April 05, 2007 01:54 pm

[Peter.N.]

Hi Stewart

With five XMs I have never had a suspension arm bush go so cant help you a lot with that one. The usual cause of knocking in the front suspension is the anti roll bar drop link.

The CV gaiter I have done several times. Loosen the drive shaft nut with the wheel still on the ground, jack up, remove wheel and undo bottom ball joint. You can now pull the hub away from the shaft. Slide what's left of the existing gaiter back away from the CV joint so you can see what you are doing. You now need a piece of metal bar that you can use as a drift, I use an old gearbox selector shaft, it needs to be fairly substantial, about 1/2' in diameter will do. Hold one end of it against the outside end of the joint as close to the shaft as possible, with a fairly heavy hammer, drive the joint outwards off the end of the shaft. Several hefty blows may be required but eventually you will defeat the snap ring. Once you have the joint off the rest will be obvious. Do give it all a good clean though, and new grease of course.

If its the n/s shaft you are doing, it will probably be easier to take the shaft out and put it in the vice, but bear in mind that you will lose your gearbox oil.

Peter.N.

[noz]

Hi Stewart,

I've got some potentially bad news for you. The bushes themselves are a doddle albeit with a hydraulic press to push them back on. A large vice will do at a push. It was the vice I used, I don't have a press.

The difficulty comes in removing the two bolts which hold the alloy spacer piece between the roll bar and the chassis. The bolts are steel and they go through clearance holes in the alloy and screw into the steel bridle which goes over the top of the roll bar. The alloy only serves to 'cup' the lower half of the bush. The problem is that in that harsh salt-laden environment there's galvanic corrosion between the alloy spacer and the bolts. This causes the alloy and the bolts to fuse as one. With a long enough bar on your socket you can get the bolt head to turn. The point of minimum strength is the shallow part of the alloy spacer and it breaks into two parts. For my silver XM I got the two broken halves off the car and punched and heated the sawn off bolt out of the alloy in the vice. I re-fitted both halves of the broken spacer back on the car with a new bush and new bolts. The steel cap and the two bolts hold it all in position so there's no real detriment to the performance of the bush.

I have never figured out a satisfactory solution to this problem. How do you break the bond between the steel bolts and the alloy spacer. (Oh, and its very close to all those nice plastic pipes attached to the steering rack or something around there so guess what happens when you try to heat it with oxy-acetylene?)

All suggestions on a postcard please....

Cheers

noz

[Zaphod]

Got the bolts off, took very little time.. but I did cheat.. pneumatic impact wrench (as foung in tyre shops) the repeated sharp shocks would apear to have losened the corrosion between the bolt and the alloy.

Stewart

[DrTim]

yeah noz interesting story I think thats what they did on mine a few years back when the bushes needed doing, went thru MOT even with cracked spacer, mechanics seemed happy enough it "wasn't going anywhere" and Mr MOT man agreed.

[Zaphod]

arghhh.. OK so the bushes were not as hard as expected.. what size is the hub nut? my biggest socket is only (?) 32mm and is too small!

For future referance on the rear bush bolts, beg borrow or steal an impact wrench, it works a treat!

Stewart

[Peter.N.]

36mm if my memory serves me correctly. I bought a 3/4" drive socket set at Trago Mills a few years ago for about £30.00. If you get yourself one, the first job will pay for it. Or alternativly, if you have a good tool shop fairly locally, just buy a ratchet and a 36mm socket, its probably the only one you will use! The 3/4" ratchet is pretty hefty, you can jump up and down on it without breaking it.

Peter.N.

[techmanagain]

Sorry to upset the applecart on this subject, but I have just confirmed with my Indie (who does my wishbone bush replacements for me) that all that is necessary is to remove the wishbone unit - bottom ball joint, front and rear nuts and bolts- grind or chisel as necessarry before pressing (or drifting ) out old bushes then press in new ones and refit to car. He says it is not always necessary even to remove the back bush; you can often get away with only replacing the front half-bushes. I pay him for 1+1/2 hours work and let him do it .

[Zaphod]

I don't think anyone was saying the rear bush should be removed from the wishbone. I certainly did not! the problems are with the bolts holding the rear bush in. They corrode to the carrier, that was certanly the case with my car but as menationed earlier the impact wrench made short work of it, not snapping of bolts, or breaking of the carrier. Had I used a socket or spanner on it I supect this woudl have been very different. Although It has to be said my rear bush on this wishbone has very little life left and I really should have done the lot

Stewart