CV joint wear

[MartinH]

Hello

I have read some of the recent posts on this subject but have a question about what is acceptable wear.

I went to a track day on saturday at Montlhery near Paris and in the final session noticed a slight clunk from the back end when really booting it out of corners. I pulled off to check it and found some play in the CV joint on one side.

Today I pulled the CV joint and found there is play which appears to be in the splines. I disassembled the shaft at the end that had the play, cleaned it and reassembled without grease. There is no apparent wear in the joint itself. The play is a few mm enough to make a clicking sound. Also the joint slides on to the spline very easily. Is this normal/acceptable? I tried to attach a video but couldn't get it to work.

I dont really want to buy new CV joints, they only seem to come in pairs for approx £700 including VAT.

Another possible source of the play/sound I was hearing is the diff itself. With the CV shaft out there is play at the inboard output shaft. These are relatively new TTR shafts with new bearings. There is no bearing play only rotational play.

I was feeling a slight rear end wandering feeling on the way to and from the track. At first I thought it might be the skinny 155 tyres getting caught in the truck grooves on the auto route. It did not wander at speed on the track.

I have recently put new Pirelli Cinturatos on the back (very good in the wet and dry on the track), set front end toe in to 4mm. I don't know if any of these factors could cause the wandering feeling.

Finally I did notice that one of the rear adjustable lower wishbones was loose at the adjusters when taking the CV joint out. Could this have had an impact on the wandering feeling?

Regards
Martin

[berni29]

Hi There

4mm front toe sounds like a bit too much to me.......

Hope you get it resolved.

Berni

[Andy8421]

Martin,

In answer to your questions:

There should be no appreciable rotational play in the spline where the driveshaft enters the CV joint. The centre of the CV where the balls run should be rock hard, and no wear should be expected there. Depending on how well the driveshaft was made, it is possible that the splines have worn, but that should be pretty clear from looking along a spline and comparing the bit that that doesn't engage in the CV centre, with the bit that does. Any step, or change in spline appearance at this point would indicate wear. You ought to be able to buy a replacement driveshaft (if that is the problem) from the supplier.

Rotational play in the diff is to be expected. The lash is the gears is necessary for the diff to function correctly.

Any play in the suspension components can easily lead to the car wandering, as can incorrect toe of the front or rear wheels. The Elan is particularly sensitive to this. Make sure everything is tight and the bushes and joints / swivels are in decent shape, then get the front and rear alignment checked.

Good luck.

[bitsobrits]

I agree with berni29 that 4mm front toe is a bit high. 2-2.5mm is what I run. What is your rear toe? Elans are very sensitive to rear toe in terms of stability at speed and through higher speed corners. I run 2mm toe in per side on the rear of my car, which is lowered with higher negative camber F&R than stock.

[MartinH]

Thanks for all the constructive comments/suggestions

It looks like it is the actual CV joint rather than the shaft which is worn. The end plate has a centre cap which looks like it has been bashed in slightly during installation/removal at various times, This has resulted in some machining of the centre cap with the resulting debris absorbed into the grease and then wearing the joint. The good news is there are plenty of these joints available, mine look to be from the Granada, GKN Lobro part number 302238 approx 100€ for the kit.

Re the toe in I am trying 4mm at the front as it definitely makes the car sharper on track. Rear toe is at 0.
One of my workshop manual specs 4.76mm for front toe in
The other has 4.76 - 1.6mm
Both have Zero to 4.76mm for the rear.
Maybe I have too much difference between front and rear?
I'll play with this to get it right.

All bushes, joints, trunnions, etc are as new with TTR shafts, Koni shocks, heavy duty wishbones and adjustable uprights. I don't run the car too low to save my wheel arches.

Again thanks for the inputs.

Regards
Martin

[rgh0]

The rear toe in specification is per wheel. The front is total toe in for both wheels. i supect you need a couple of mm of toe in at the rear on each wheel

regards
Rohan

[MartinH]

Thanks Rohan
I set the rear toe as per your suggestion and re-checked the front. This has completely cured the wandering sensation and the car feels very nimble now.
Martin