Rear Wheel Bearings: a Query

[tonycharente]

Hello all,
Sorry if this seems a repeat, but I have just spent half this evening searching on the many Wheel Bearings threads but I don't think there is an answer to this specific question.

With the car (Elan S4 with double UJ drive shafts) jacked up I can feel a slight play rocking the rear wheel, same play holding tyre at 6 and 12 o'clock as at 3 and 9 o'clock. It's the same both sides of the car, and I have checked the shaft nut is properly torqued up (as well as the wheel nut...) The question is should I simply not be able to feel any play at all, or is some play normal - and if so just exactly how much play at the wheel rim is normal?

Obviously I am fearing wheel bearing problems - but I have no bearing noise and if I stop after driving a while without braking there is no heat build-up. So I don't want to change the bearings if they are in fact normal.

Many thanks
Tony

[mark030358]

Sounds like bearings to me, as they are parallel and not tapered. Could you be feeling play in the drive shafts or suspension bushes though?


cheers
Mark

[Hamish Coutts]

Tony,

You should not feel any play. Are the bearings noisy when the car is running?

Sorry to be a pessimist but it may be that the outer driveshafts are a loose fit in the bearings. My MOT tester found play in the rear offside wheel and it turned out to be just that. You may be able to get away with this by using some of the bearing seating compounds to get a tight fit but then again, it may be you need new outer driveshafts

Regards,

Hamish.

[ppnelan]

My suggestion:

Keep using it , keep an eye on it but don't get paranoid , and sort it out if it becomes a real problem ...

Matthew

[rgh0]

Tony a very small degree of play is acceptable. At maximum you can just be able to feel at the wheel rim. If measured at the hub with a dial guage it should be only a couple of thousands of an inch maximum either in out or up down or sideways. More than this and you have a bearing or bearing mounting problem.

If you feel you have movement make sure its not the hub moving on the strut or on the wishbones rather than the shaft in the hub before you start pulling things apart.

regards
Rohan

[tonycharente]

Tony's replies and further info:-

Mark: I can feel no play in the drive shafts or suspension bushes

Hamish: The bearings are not at all noisy when the car is running, and after a long run and slowing to a stop without braking the hub assembly is as cool as a cucumber. It's these two factors that make me reluctant to replace the bearings (yet!!!).

Mathew: "Keep using it, keep an eye on it but don't get paranoid, and sort it out if it becomes a real problem" - yours is the advice I like best! But once the paranoia sets in, it's hard to get rid of.

Rohan: Please see my "update" below - your further analysis would be most welcome.

Tony's update: Taking account of all of the comments so far, I checked out the play again. With the car sitting on it's four wheels, I can feel no play at all. (Whereas I can feel a little play on the front wheels like this, but that, I believe is correct). With the car jacked up and the rear wheel "hanging", and equally with the car jacked up on the lower wishbone (weight spread across all the bars, of course...), and with my patient wife rocking the wheel, I can feel no play anywhere in the suspension bushes, nor movement of the damper assembly, nor can I detect any movement of the brake disc, but there IS movement at the wheel. This movement can only be felt when rocking the wheel (hands at 6 and 12 o'clock and also at 3 and 9 o'clock) - I can feel no play at all pushing or pulling the wheel straight in and out. Also, it has to be said that in fact there is more play when rocking with hands at 6 and 12 o'clock than at 3 and 9 o'clock - which I feel must mean something - but what?

All further comments welcome, please.
Thanks, Tony

[Hamish Coutts]

Tony,

Sounds one of two things to me:

1. A loose hub, which I doubt as you said previously that the retaining nut was tight.
2. More likely, a worn outer driveshaft making a loose fit in the wheel bearing. Most probably the shaft is a loose fit in the outer bearing, though when I replaced mine, the fit to the inner bearing wasn't too clever either.

Can you take the hub off to have a look at where the shaft exits the bearing?

Hamish.

[tonycharente]

Hamish,
Many thanks, but 3 more questions, please:-

(1) Yes, I can certainly see that a worn outer driveshaft making a loose fit in the wheel bearing, with the bearing itself in good condition and spinning freely, would explain the absence of noise and of heat generation, the absence of in and out play, and my inability to feel any play when the car is on its four wheels, so the weight is on the shaft. But why would it give more play when when rocking the wheel with hands at 6 and 12 o'clock than at 3 and 9 o'clock?

(2) Is it possible to take the hub off to have a look at where the shaft exits the bearing with everything else in situ? How would I do that, please?

(3) If it is the shaft making a loose fit in the wheel bearing, then I take it the solution is the full same horrid job as replacing the bearings with a new shaft to buy thrown in on top? Or is there an easier fix if the bearings are OK in themselves?

Thanks again
Tony

[reb53]

Don't know how much a new shaft is but I recall many years ago getting mine metal/plasma sprayed and re-machined when I found it had a groove worn in it. It's been fine since so the repair worked OK.
The 12/6 and 9/3 problem is interesting!
Could the plain bearing at the top of the shocker be worn? This would allow 12/6 movement but not 9/3. They certainly do wear as I saw this on my car before replacing them with Koni inserts. HUGE improvement.

Ralph
71 Sprint.

[rgh0]

Difficult to diagnose movement of a hub just by feel. You really need to put a dial guage on it. Lateral rocking movement much easier to feel than in out or up down movements of the same order of magnitude because of the lever arm the wheel provides. The magnitude of rocking is also greater for the same bearing internal float as it involves both bearings going to opposite ends of their float radially plus its magnified by the distance between them.

If its definitely movement between the hub and shaft then it is either wear / normal tolerance in the bearing or a problem inner or outer bearing mounts on the hub or shaft not being a proper interference fit. If the movement is a max of a couple of thou in the plane of the bearing between the hub and shaft then most likely just bearing tolerances and Ok. if any bigger then a badly worn bearing near failure ( which should be noisy) or a loose bearing fit somewhere.

If I was doing the job I would carefully measure the shaft end float and lateral movement with a dial guage and if movement was too great then diassemble to diagnose the cause and fix.

regards
Rohan

[Hamish Coutts]

Hamish,
Many thanks, but 3 more questions, please:-

Tony,

I think Rohan has answered your questions to me very well. Thanks Rohan!

Hamish.

[tdafforn]

Outer drive shaft is around ?100...
I know after a well known suppier bent 2 of mine while removing the hub
tim

[tonycharente]

Thanks again to all.
UPDATE: Had another session trying to find any movement anywhere other than in the bearings area, including trying to feel any movement at the top of the shocker, strut to hub, suspension; none found. So all the play I can feel does seem to be coming from the bearings area - either the bearings or the shaft I presume. I have no bearing noise or heat build up, though, and the play is only slight - and none at all felt at all straight in and out, only on rocking up and down. So I've decided to prepare for a bearings change by getting all the parts in, but to wait and see before stripping it all down.
RESULTANT QUERIES: Is there any reason why I shouldn't buy in all the parts before stripping it all down, and what do I need to buy other than the bearings themselves, please? Also is/are there any Elan specific tool/s I should purchase?
Thanks again,
Tony

[Hamish Coutts]

Tony,

It really looks like it is wear in the outer drive shaft. Check with the likes of Matty or TT. I got a new TT shaft via Matty when I got a lot of other stuff. Seem to remember it cost a damned sight more than ?100.

Mind you, after doing the replacement it feels a hell of a lot better. There is no movement in the hub. Here's hoping for the next MOT in July!!

Hamish.