Rear wheel bearing.

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DaveEFI
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Rear wheel bearing.

Post by DaveEFI » Wed Jun 14, 2017 8:35 am

Looking for some info from some of the experienced types on here.
On the SD1 forum, a member removed a halfshaft from his axle. It came out with the outer part of the bearing still in the the axle housing. Ie, the rollers exposed. The outer wasn't difficult to remove from the housing and according to him looked OK. I've stripped a few of these axles, and the halfshaft has always come out with the bearing complete. So wondered exactly what had happened?


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Post by JSF55 » Wed Jun 14, 2017 10:43 am

Wear on the half shaft would allow the bearing to be stuck in the housing, measurement of the half shaft should confirm this. The other possibility is a loose axle housing that's had the bearing changed and some "bearing fit" applied to it, this can cause it to be come stuck

http://www.loctite.co.uk/news-4082_bear ... E_HTML.htm
So thats where it went !

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Post by DaveEFI » Wed Jun 14, 2017 11:56 am

Think you misunderstood. The bearing is a ball race. Which is supplied as a complete unit. It is very firmly held in place on the shaft by a collar pressed in place with a force of several tons. The outside of the ball race fits into the main axle housing, and is held in place by a bolted on plate. You remove that plate to remove the halfshaft assembly complete. As far as I can see, the ball race itself contains any sideways movement of the shaft. Ie, sets any end float. So can't understand how an apparently good one can separate.
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Post by harvey » Wed Jun 14, 2017 2:53 pm

DaveEFI wrote: The bearing is a ball race.
IIRC they are a taper roller bearing, which is far more likely to leave the outer track in the axle housing. I can't see it ever happening with a ball bearing, if it did then the bearing would probably just fall apart.

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Post by DaveEFI » Wed Jun 14, 2017 4:16 pm

harvey wrote:
DaveEFI wrote: The bearing is a ball race.
IIRC they are a taper roller bearing, which is far more likely to leave the outer track in the axle housing. I can't see it ever happening with a ball bearing, if it did then the bearing would probably just fall apart.
Yes- I was trying to keep it simple. The BL manual does show it being a taper bearing.

I've no real idea just such things are constructed. But it obviously has to take at least some thrust in both sideways directions.

The front wheel bearings are a pair of taper bearings, and they come apart if you remove the hub. But easier to understand how they work.
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Post by harvey » Wed Jun 14, 2017 4:51 pm

If it relies on friction between the outer track and the casing to hold the halfshaft in place then I wouldn't want the bearing to split when removing it, if it's held in place by a plate and the backplate I can't see there's a problem, other than getting the outer track out of the casing.

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Post by DEVONMAN » Wed Jun 14, 2017 10:17 pm

I think this particular bearing had seen better days.
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Post by russell_ram » Thu Jun 15, 2017 8:25 am

DaveEFI wrote: The BL manual does show it being a taper bearing. -
AND - it obviously has to take at least some thrust in both sideways directions. - AND - The front wheel bearings are a pair of taper bearings, and they come apart if you remove the hub. But easier to understand how they work.
If it is a single taper roller (as most beam axles are actually) then you do have a PAIR of tapers to oppose cornering forces in exactly the same way as your front hub assembly example - they are just on opposite ends of the axle. The lateral force that would separate the taper on one side of the car is transferred along the driveshaft through the centre of the diff via a spacer to the one on the other side.

See the first pic here for instance (first one I could find quickly that shows what I mean) : https://sites.google.com/site/morganati ... fferential.

It shows the taper roller in one hub (that couldn't resist inward forcing in this instance) and the spacer inside the diff which transfers that forcing to the other shaft / side of the axle (which can resist that force 'cause it's bearing is facing the opposite direction).

Hope that makes sense but that's how most beam axles work.
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Post by DEVONMAN » Thu Jun 15, 2017 8:49 am

What is odd in this case is that the bearing came outwards
without the outer part therefore not resisting outward movement of the shaft. Maybe the bearing was inserted back to front.

Inward movement should be resisted by spacer in the diff and the opposite shaft, and outward movement by the bearing.
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Post by SuperV8 » Thu Jun 15, 2017 10:29 am

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Post by DaveEFI » Thu Jun 15, 2017 12:24 pm

DEVONMAN wrote:What is odd in this case is that the bearing came outwards
without the outer part therefore not resisting outward movement of the shaft. Maybe the bearing was inserted back to front.

Inward movement should be resisted by spacer in the diff and the opposite shaft, and outward movement by the bearing.
I wondered about that - but the pic showed the rollers to be in the same direction as in the BL manual drawing.

it's obvious (to me) there will be more sideways thrust when cornering in one direction - but surely still some when cornering the opposite way?

Thing is that if the bearing itself doesn't contain that 'reverse' thrust, if would be done by the oil seal.
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Post by DEVONMAN » Thu Jun 15, 2017 1:54 pm

DaveEFI wrote:
DEVONMAN wrote:What is odd in this case is that the bearing came outwards
without the outer part therefore not resisting outward movement of the shaft. Maybe the bearing was inserted back to front.

Inward movement should be resisted by spacer in the diff and the opposite shaft, and outward movement by the bearing.
I wondered about that - but the pic showed the rollers to be in the same direction as in the BL manual drawing.

it's obvious (to me) there will be more sideways thrust when cornering in one direction - but surely still some when cornering the opposite way?

Thing is that if the bearing itself doesn't contain that 'reverse' thrust, if would be done by the oil seal.
The rollers shown in my SD1 Haynes manual are the opposite way round to the drawing of the Salisbury Axle shown by Russell_Ram. In the case of the Salisbury axle the trust is taken by the bearings in the outward direction and the inward thrust is transmitted to the other side of the axle via the halfshaft and centre spacer.
Maybe Mr HAYNES has got it wrong in his book or the SD1 bearings are special rollers that take thrust in both directions. There is no talk of checking the axial end play in the SD1 book.
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Post by DaveEFI » Thu Jun 15, 2017 2:50 pm

I've only got the BL manual. Here's the pic from the SD1 site:-

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