Wobble between 60-80kph

[HatandClogs]

Hi Everyone, got a problem that I need a bit of help with. When I accelerate between 60-80kph I get a wobble that is worse the faster I accelerate and stops if I stop accelerating or when I reach 80. It seems to be worse on the left hand side at the front (RHD XM).

I also just had new tyres put on with an alignment and balance so its not the wheels. The CV joints and wheel bearings are also good. I spoke to a mechanic who suggested that it is most likely my axle, possibly a worn triaxe joint, split boot or the support bearings. But because my knowledge is pretty limited I don't really know how hard they would be to check or where exactly they are located (thought I understand the support bearing is on the back of the sump so I don't think it is that).

Has anyone had any experience with checking the axles, repairing them or had the same issue? Or does anyone have any other suggestions to what it could be?

Thanks!

[xmexclusive]

The wheels are the last thing changed.
If this wobble is new or much worse than before then prove it is not the wheels first.
Assuming they are new so must be correct and well balanced could have you spend money on other minor faults only to still have a problem.
Swap the wheels front to back and check the car ride again.
If there is still a problem get the balance of one wheel rechecked on a different balancing machine.
What type of wheels? Centreless Alloys often do not get balanced properly.

John

[Peter.N.]

If the wobble was there before you changed the front tyres - suspect the rear ones. Probably 95% of vibration problems are wheel/tyre related. Sometimes the balance is OK but the tyres have bulges due to ply seperation that only show up at speed.

Peter

[HatandClogs]

There is only one place where I live that can balance my wheels, or align them, and from what I can work out they have done a good job since I have no vibration or wobble at 140kph. I also got four new wheels and the wobble was around before then (got them balanced once before and that didn't fix it, I thought then it was just my tyres getting old). There is also no vibration that comes with the wobble, it doesn't come through the steering wheel and I can let it go and the car doesn't veer off the road, even a little. That's why I don't think it is the wheels...

I had one more thought, and that was that my spheres need re-gassing. I know the feel for a DS but I'm not sure what it would be like or how an XM would act.

[xmexclusive]

I have had experience of support bearing failure.
In hard acceleration it gives a lateral wobble to the front end.
The drive shaft is oscillating but it takes a lot of inertia to do this.
Each gear will have a different critical point/speed giving maximum wobble.
First gear will be less noticable.
Second and third will give significant amounts of wobble.
Fourth and above you will not be able to get an XM to accelerate fast enough for noticable wobble.
I think the wobble increases under very high torque then decreases again as the car gains speed and cannot maintain that level of torque in that gear.
The bearing is difficult to examine insitu.
Replacement bearing or exchange drive shaft are the options.

John

This post has been edited by xmexclusive on February 02, 2012 12:56 pm

[Peter.N.]

I have only had one occurance of non wheel balance vibration and that was on a CX with worn innner driveshaft joints, that only occured on a long journey when the shafts had got hot and the grease thinned and varied with the ammount of throttle applied, the car had done over 200,000 miles though.

Peter

[HatandClogs]

what you are saying John sounds close, but it doesn't matter what gear i'm in. I can leave it in 2nd or 3rd and the wobble disappears even in high revs (at 3000 revs in third i hit 80kph and the wobble stops) and in 4th the wobble is there even though revs are low (1700 give or take 100). Was your bearing failure really precis? or was it around most of the time?

and Peter my XM has done 118000 miles so maybe thats enough for it to weaken even though the wobble started just driving around town?

[xmexclusive]

Hi H&C

The car was a V6 estate with around 160k miles.
I tried all the usual suspension checks without finding or curing it.
It got slowly but progressively worse during the couple of years I used it.
The motion was unusual in my experience of cars.
Rapid lateral oscilation of the front end.
A motion I actually knew well as "hunting" from work as a railway track engineer.
Where an unstable vehicle at speed uses its wheelflanges to bounce back and forth between the rails.
The car was turned into spares mainly for a number of other reasons.
The front suspension was stripped expecting to condem it all.
Surprisingly virtually everything was good and much has been reused.
The only major fault was that the driveshaft support bearing had collapsed and all the balls were missing. There was steel scuff marks suggesting that the inner and outer
rings of the bearing had been rubbing on each other.
Because the car was not repaired and checked I cannot be certain.
I can only suggest that you check out the condition of the support bearing on your car.

John

This post has been edited by xmexclusive on February 03, 2012 04:40 pm

[Peter.N.]

I also have had the centre bearing fail only in my case it gave no symptoms until the shaft fell out of the diff and I lost drive but could well be worth consideration though.

Peter

[techmanagain]

I have had this on a CX and like elsewhere suggested, it was the bearing in the drive shaft at the back of the gearbox. I think the clue lies in the fact that it does not happen on the overdrive (ie not accelerating).I would say that it is without doubt drive shaft related.

[HatandClogs]

Thanks guys, I'll go find a mechanic and get them to have a look. Anyone know a good place to get XM parts?

[Peter.N.]

I used to get mine from GSF but ebay is often cheaper now.

Peter

[xmexclusive]

If it is just the bearing gone then it my be possible to replace just that.
Ebay now seems devoid of XM drive shafts.
Not see any new old stock items for a while.
A shaft refurbishment firm listed a clear out in available a few months ago.
I got a short one as stock for my 2.5's but they had no long ones to suit.
If your "down under" note means Aus or NZ then our advice may not be ideal.

John

[HatandClogs]

I am in Australia so no matter what I will have to ship the part over here. I found one left hand driveshaft (left is the short side right? does it change between LHD and RHD XMs?) on ebay, in England, seems fairly cheap at $120 (around 90 pounds). The wobble does seem to come from the left side, or so all my passengers tell me (took a mechanic for a spin and he reckoned it was the left side before I told him anything). Its the only one I can find so it will probably have to do. Is that money alright? And would you know if any Citroen dealers/mechanics in France would still have XM parts, or ways of obtaining them?

[xmexclusive]

LHD and RHD XM's use the same drive shafts.
There are very significant differences between the two shafts.
The drive points for the shafts are where the engine and gearbox mate together.
Well to one side of the car centre line.
The shaft have drive splines but are just a push fit into the drive points.
The left hand shaft is made up of 3 short lengths with simple CV joints.
Despite only being bolted at the wheel end there is far too little play in its short length for it to come anywhere near dropping out of the drive point.
The right hand shaft has one much longer length across the back of the engine.
It is this long length of shaft that needs the extra bearing to control its inertia and prevent ite drive spline dropping out its drive point.
Peter has confirmed that a failed bearing can let the long shaft drop out.
The housing and extra bearing are at the opposite end of the engine to the gearbox.

I would be very surprised if the short shaft turns out to be the cause of the wobble.
There is every chance that the only fault with the long shaft is the bearing.
It is a fairly standard bearing common to many PSA cars.
It should be available locally without needing to source from Citroen.
Similarly drive shaft overhaul is normally carried out by local firms over here.
I would expect it to be similar over there.
Someone like Addo may know. I will check if he is a member here.
If not he can be found on FCF.

John