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MG MGB Technical - Rear Wheel Free Play (Steel Wheels)

Help

At my last MOT a slight play was noted in my rear o/s whel when holding and rocking the wheel.

I have just had the rear o/s wheel bearing replaced by a MG approved garage and have noted some days later that the free play or wheel movement is as it was before the bearing was replaced.

I will be returning the car to the garage for comment but was wondering just what could be causing the problem:

Are we looking at play in the hub to half shaft shaft splines if so is it the hub or half shaft??? I would assume the half shaft is case hardned.

or is it something more sinister????

As the work was done by a 5 Spanner garage I assume it has been has been torgued to 150?

I look forward to your comments

Gordon
G Hind

Gordon,
I suspect that you will find the hub and half shaft are rock solid but it won't do any harm to check the torque setting. If the whole wheel and hub can move in and out, the spacer inboard of the wheel bearing may be compressed. If the wheel and hub can be rocked - the problem could be with the inner bearing.
Please keep us briefed.
Roger
R Walker

Are the lug nuts tightening down completely on the wheel? Cheers - Dave
David DuBois

Hi Roger

Thanks for the update.

I have checked for lateral movement and there is none so the inboard spacer is ok.

The inner wheel bearings are new (10 days ago)

So where does this leave me???

Regards

Gordon
G Hind

Hi David

Yes the lug nuts are tight.

Regards

Gordon
G Hind

Can *you* feel rocking? If so remove the wheel centre cap and see if the nut and shaft are moving with the hub or independently of it. There have been reports that even when the hub nut is tightened to the correct torque the hub is still loose, although looking at my old axle there is no way the hub can contact anything before the tapered oil seal collar.
PaulH Solihull

What you are left with is wear on the dif/half shaft gear, within the dif carrier. A common problem as the parts are NLA and axle re-furbishers choose to ignore the problem and hope for the best. Quite often you will hear the brake drum catching the back plate! Replacing the pinion shaft and thrust washers might improve it a bit, but until someone bites the bullet and manufactures the dif gears again wew are up the proverbial and paddleless!!
Allan Reeling

Whilst diff wear will cause the clonk I can't see it causing the wheel to *rock* (some rotational play with the other wheel and propshaft locked and handbrake off is inevitable). The wheel bearing is a ball running in a channel, not rollers running on a plane like the fronts, so no play should be evident on a good bearing. The inner end of the half-shaft would have to be moving a huge amount for it to be detectable at the wheel. The bearing inner should be pressed up against a spacer which is pressed up against a shoulder on the half-shaft, and the bearing outer is pressed into the casing, with the hub tightened onto a taper which is pressed against the bearing inner, so I don't see how you can get any in and out movement of the hub either. The distance between drum and back-plate shouldn't be that critical, they are hardly precision components.
PaulH Solihull

Hi Paul and Allan

Thanks for the information I will carry out further checks - the problem is only associated with the o/s/r - the other side is rock solid. Also I am not aware of any clunking or other noises comming from the back end.

Regards

Gordon
G Hind

Gordon,
Paul's advice about the possibility of movement at the diff end of the halfshaft is compelling you would think that unless the hub is moving on the halfshaft, the movement would have to be on the inner end. However, I have just had a feel of my V8 and there is a little movement on the starboard wheel but not on the portside. Like you, I fitted a new outer bearing a few thousand back - if the groove in the roller bearing was only fractionally too big...... mine's in for MOT in a couple of weeks... I will get an opinion on bearings then.
HTH
Roger
R Walker

Only other thing I can think might contribute is wear on wheel mounting points. I know you have checked the wheel nut tightness, I wonder, any wear (uniform or irregular) in the wheel facings where the studs pass through or nut faces contact?

Have you tried swapping wheels side to side to see if the problem moves or disappears? Tried the spare? I know my spare wheel has been relatively little used over the years.
Roger T

I actually meant to say "Other than the suggestions above, the only..." Sorry for the unintended blunt opening.
Roger T

Well whether it seems lokely or not, I can only say what I see. This has happened to me when I was conscious of the drum rubbing the backplate. After replacing the outer bearing, the wheel rock still persisted, as did the back plate catching. So, up in the air, diff cover off, and look. With a friend rocking the wheel it was easy to see the movement in the half shaft and gear! Up to now I have put up with it, but have "acquired" the said gears. .....Winter job, on top of all the others!!!
Allan Reeling

It's pretty common on RWD live axles (mostly small trucks for moderns) More when the wheel is rocked with hands at 6 and 12 oclock as opposed to 3 and 9 oclock

As a tester I/we advise them if we think the customer might be interested, but so long as the "big nut" is tight it ain't going anywhere! Personally I wouldn't worry-it's just old! Wait till it whines!
Michael Beswick

Hello

To all who have sent information - many thanks.

I have returned the car for investigation - today a new bearing was fitted with a new half shaft?? unfortunatley the hub would not fit the new shaft.

Old shaft replaced and now I find I have play both at 12 & 6 and now 9&3.

Is it possible that the taper outer collar and or the inner taper of the drive flange is worn.

What would be the effect if the bearing spacer was not fitted?

Look forward to feedback please

Gordon
G Hind

"Is it possible that the taper outer collar and or the inner taper of the drive flange is worn."

Yes. And this causes the nut to tighten against the thread bottom (most common) or spline shoulder. In either case, the nut is tight but the hub is loose. I have had to fit a large washer under the nut a few times to allow the hub to be clamped correctly. If the drum rubs on the backplate, assuming the backplate is not bent/damaged, then the wear is sufficient to allow the hub to be inboard too far. The entire spacing of the hub is referenced off the bearing, which is positively located in the housing, so any wear from the bearing out will reduce the drum-backplate clearance. If the wear is this severe, the more appropriate repair would be to fit a spacing washer between the bearing and the taper collar (or replace the hub and collar).

"What would be the effect if the bearing spacer was not fitted?"
You would have the same premature tightening of the nut, but not the rubbing on the backplate, until the hub wear has progressed to the same state as previous.

It is the hub running loose that causes this wear, and also wear on the splines of axle and hub, and the dread "clunk". Couldn't tell you how many cars I've seen this on.

The inner end of the axle does not enter into it, unless the gears are actually disintegrated, in which case we would not be having this discussion! There will always be a very slight movement in the axle/gear, since the inner end does in fact keep things lined up, but that is normal. I would expect something on the order of .010max total movement at the gear on worn axle/gear/diff carrier, and the resulting movement at the tyre tread would be about half that with a good bearing. That is at the limit of what most people can feel, so if you have more it is not from the inner end wear.

FRM

FR Millmore

Many thanks FRM

I will take on board your advise and investigate more. I do not have any back plate rubbing at all so before I go back again to the garage I will investiagte play at the Drive Flange end.

Regards Gordon

G Hind

Hello again FRM

I have tried your idea of the washers under the hub nut and it makes no differance - I still have play at 12&6 and 9&3.

Regards

Gordon
G Hind

Gordon-
Are you certain that the nut/washers are not bottoming on the spline shoulder? I have seen this once or twice when wear is severe. In that case, you have to grind off the shoulder a bit or make a washer that will fit OVER the splines and keep it centered as you tighten the nut.
You would get the same thing if the bearing spacer were missing, but I suspect that even if you got it tight, the bearing would move in use until it is loose again.

FRM
FR Millmore

Hello again FRM

Today I removed the drive flanges from both sides of the axle (bearing in mind there is no play what so ever in the near side)

I transposed the drive flages and split cotters (good to bad - bad to good)

The result there was still play in the off side now fitted with the near side bits while the near side was free of all play - as it was before the change over.

This excercise proved that the play on the off side is not the result of any wear on the drive flange or split collar.

If I had the room in my garage I would pull both shafts and bearing and swop them over to see if that made any differance.

Still will keep trying.

Regards

Gordon

G Hind

Gordon -
Well, now you are making it difficult!
Don't suppose you measured the exposed lengths of the axles ends while you had both sides apart?
Other than machining differences, the only thing I have left to suggest is removing the loose side axle and checking for the presence of the bearing inner spacer collar.
The other remote possibility is that the replacement bearings are narrower than the correct one.
I am curious to hear the final cure!

FRM
FR Millmore

Hello FRM

Yes I did measure the lengh of exposed shaft from the cone spacer to end of shaft and they were both in the order of 80mm.

I have even changed the cone spacers over and still the play exists.

The only items which have not been changed over are the shaft with bearing and spacer.

The near side now has the drive flange, split collar and cone spacer from the off side and still no play exists on the near side.

I will keep you informed on any out come.

I will probably purchase a new bearing, seal and nearing spacer and have them fitted by the garage that carried out the original works - at least the bearing will not have came from the same source.If you remember the new shaft they were going to fit would not accept my existing drive flange - quality control????

Regards

Gordon
G Hind

This thread was discussed between 21/11/2011 and 04/12/2011

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