Rear wheel bearing end float.

The solid rear axle on the SD1 is of the semi floating type. So only a single wheel bearing.
What sort of end float would be acceptable? Don't think it can be zero
with a single bearing?
Can't find a spec in the BL workshop manual.
--
*He who laughs last has just realised the joke.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/08/2015 13:22, Dave Plowman (News) wrote:

If you know the type of bearing (almost certainly an ISO standard bearing) the manufacturer's catalogues will tell you the tolerance range of radial clearance. If it is an interference fit on the shaft or in the housing, this will reduce the radial clearance. There is a relationship between the axial and the radial clearance.
But if you are saying you have an axial clearance which causes you concern, this sounds like a bearing with fatigue (or just possibly wear). In which case it is likely to be noisy enough to prompt you to replace it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Looks like a pretty standard bearing to me. I've not attempted to change one, but it is held in place on the half shaft by a collar which requires a large press to set. The assembly is a relatively easy fit to the axle housing - only needing a couple of levers to remove, once the clamp plate is off.

It's not actually my car. But the one in question was an MOT fail, but the bearing quiet. The MOT place didn't say what the end float was - but simply in their view excessive. It's common to get an advisory (or worse) on the front wheel bearings which are adjustable - even when set to the correct spec. Of course perhaps most modern cars have twin wheel bearings under pre-load so zero end float if good.
Hence looking for a figure to argue about. ;-)
--
*A clear conscience is the sign of a fuzzy memory.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 03/08/2015 11:06, Dave Plowman (News) wrote:

I'll ask my mechanic mate next time I see him. I suppose it is possible that the collar was not pressed on properly, and perhaps there has been fretting wear either on the shaft or the shoulders so that now the bearing is a bit loose. ISTR that a millimetre or two of "rocking" movement at the rim is not uncommon.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

No rocking movement. Would be surprised if there were since the half shaft is long. For there to be any rocking movement it would mean up and down play in the bearing? This is pure in and out movement.
I'd be surprised if it was movement between the bearing and housing or shaft. If that were happening, I'd expect it to get worse very quickly as those areas wear.
The owner reckons this play has been there for a long time without changing. Just assumed it was normal.
--
*I started out with nothing, and I still have most of it*

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 03/08/2015 13:01, Dave Plowman (News) wrote:

You are quite right, there should not be much rocking, I was thinking about wheels on stub axles.
It's a single bearing so it must be a "locating" bearing, i.e. providing axial as well as radial constraint. It could be a deep groove or a cylindrical roller. In either case there will be some radial and axial clearance. Bearings are manufactured in different clearance classes (C1, C2, C3 etc) and the values are quoted in the catalogues. For example a 6310 (which sounds about right to me, 50 x 110 x 27 mm) with standard clearance would have a *radial* clearance between 6 and 23 microns. This is the figure for an unmounted bearing, if it is mounted with interference either on the shaft or the OD the clearance is reduced. There is a relationship between radial and axial clearance, but it is complicated because it depends on tolerances in the radius of the grooves in the axial direction. My recollection is that the axial clearance can be a couple of times the diametral clearance, so say up to about 0.1 mm for that bearing. For a bearing with grease in it, you will be hard pressed to detect that by "feel" and you would need a fairly good metrology setup to measure it on the car, even with the wheel off.
So, if someone is seeing more than that I think you would be looking at a bearing with severe fatigue pitting in which case you should hear it grumbling when you drive (although you might have to coast with the window open) or the bearing is moving in the housing or the shaft. I wouldn't like to predict how long that might last.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The bearing in question is quiet.
Bit more info has surfaced. Seems the owner noticed some end float many years ago, but ignored it. And it's only been seen as a problem at this MOT.
My view is if the bearing were moving on the half shaft or in the housing, any float would soon get worse. Steel to steel plain bearings ain't a good idea. ;-)
--
*Save a tree, eat a beaver*

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 02/08/2015 13:22, Dave Plowman (News) wrote:

saw this: http://www.tr-register.co.uk/forums/index.php?/topic/29696-rear-axle-endplay/
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

http://www.tr-register.co.uk/forums/index.php?/topic/29696-rear-axle-endplay/
Thanks for that. Seems it's quite common. It is a major job to change the bearing - especially if there's no guarantee the new will be better. These bearings don't often fail so it is likely the original. And new stuff for old cars seems so variable in quality these days.
--
*Taxation WITH representation ain't much fun, either.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 03/08/2015 18:50, Mrcheerful wrote:

Interesting link. So a few mm is not uncommon. Do you know if this is a roller bearing or a deep groove? I just don't see how it can be clearance in the bearing itself (unless it is very worn).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 04/08/2015 22:08, newshound wrote:

I read it that the bearing itself is moving in the housing and some shims could reduce that movement to zero. The bearing cannot move on the shaft because there is a great big steel ring pressed on to hold it there (I have once changed one) The bearing will not have that much play, so logically it must be sliding back and forth in its housing in the end of the axle tube.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 04/08/2015 22:30, Mrcheerful wrote:

Sounds pretty plausible. I wonder what the design logic was. You don't need the float for differential thermal expansion, you have the spline into the diff for that. Since the basic "gravity" load between the outer race and the housing is always in the same direction, the bearing OR can be a light sliding fit in the housing. (The "rotating load at the inner means that the bearing will creep on the shaft, eventually leading to fretting wear, unless it is a press fit).
Perhaps the really high float ones are where the axle has been apart and rebuilt leaving out the shims!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If it were moving in the housing over a period of time, wouldn't this soon result in that housing wearing? But it is clamped in place. It would be easy to shim it to increase that clamping pressure if needed.
I think it is a plain ol' ball bearing. I do have a spare axle here and could check.
--
*I'm not a complete idiot, some parts are missing *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/08/2015 11:02, Dave Plowman (News) wrote:

If a ball race had sufficient play to pull the shaft in and out enough to feel, there must be up and down play and roughness. I went hunting for a half shaft, but I think I must have scrapped all of them long ago, pity.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/08/2015 11:15, Mrcheerful wrote:

Agreed.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I'm told there is no noise from the bearing.
--
*A journey of a thousand sites begins with a single click *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/08/2015 13:47, Dave Plowman (News) wrote:

So it must be moving in and out, most likely in the axle tube.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/08/2015 11:02, Dave Plowman (News) wrote:

It's the inner race which is clamped on the shaft. The outer race sits in a housing between two shoulders which are slightly further apart than the race width, which is where the movement takes place. Yes, you are correct that this in and out movement should lead to some wear. But what *really* causes wear is when a race rotates in its housing or on its shaft. This is only a risk on the race with the rotating load, i.e. the inner, in this case. Rotation is prevented by having the race a sufficiently tight fit on the shaft. People sometimes hope that they can cure a rotating race by axial clamping (e.g. by adding shims) but this does not work. If there is any radial clearance (even minuscule) plus a rotating load, the race will creep around and eventually cause fretting wear, initially recognisable by a red "stain" of oxide, on both parts.
On reflection, this must of course be a ball bearing, most likely a deep groove; a single roller bearing would be destroyed rapidly by the cornering forces.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/08/2015 12:44, newshound wrote:

Logically to cure in out movement if the bearing is OK, just remove the shaft, shims into the end of the axle and re=assemble.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 05/08/2015 12:55, Mrcheerful wrote:

Agreed.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.