Morris Minor Owners Club

Long post....long day.


It seems that you get problems with the rear hubs, or you don't. Or you might have a problem, but don't know it. Confused? Join the club.

I have a 5.37 diff which I'd only use as a temporary measure if all my other diffs failed. It's in an excellent axle casing so I decided to strip it and get the parts boxed up and labelled. It didn't take long to notice that each hub was sliding excessively in an out. No rocking with the wheel on....just sliding in an out - definitely an MOT failure. I've had this problem before and have gone through all the threads relating to rear hub issues.

The cause of the problem is that the large bearing is not a tight fit in the hub. There's no gap allowing the hub to wobble on it, but it can be pulled out with a light pull using just a couple of fingers. I started thinking about the whole configuration, and the more I though the less it made any sense at all.

Many Moggie owners report problems of oil in the back brake drums, caused by seepage between the hub and axle shaft flanges. Some hubs have a groove for an O-ring to keep the oil out of the drums, others just have a thin paper gasket.

The main thing I don't understand is this:

The bearing is fixed to the axle by a large nut with a lockwasher. The bearing is obviously put into the hub before assembly. But there is nothing to stop lateral movement of the hub, as far as I can figure, other than the friction between the bearing outer face and the corresponding face in the hub.

Once the hub starts to slide on the bearing, there's nothing to stop it moving towards the centre of the axle. The hub can move inwards until the halfshaft comes into contact with that pin in the middle of the diff around which the small planet gears rotate. Surely this would not be desirable....having the halfshafts hammering on the pin. Well, perhaps not quite hammering, but making contact with it.

I did a lot of messing about. Without the paper gasket and the hub in the correct position, the halfshaft when fully inserted, made contact with the pin - the distinct knock makes this apparent. With the original thin paper gasket in place, the halfshaft didn't make contact with the pin. I tried a thicker gasket which someone had made up from cork, and this increased the amount of lateral movement of the hub on the bearing.

On all the hubs I have, the outer ring of the bearing is slightly proud of the hub flange. I've read here that it should be flush with it. I placed a cigarette paper betwen the outer bearing ring and the back (inside) face of the halfshaft flange. With everything in the proper position, the cigarette paper was held firmly between the bearing and the halfshaft flange.
This showed that the halfshaft flange is touching the outer bearing ring. But when I firmly pulled the hub and halfshaft flange assembly outwards, as one unit, the cigarette paper was freed. This is weird, because the hub and the halfshaft flange were firmly together, movng in unison

I inspected further, and noticed that there was in fact some lateral free play of the balls in the bearing and the races, allowing the hub to move slightly laterally even when held firmly together with the bearing....by a few thou. As I've said, there was no rocking of the wheel fitted to this hub, but I concluded that the bearing is in fact worn. That's why I wrote that some owners may have a bearing problem they don't know about. Or maybe this is normal bearing float?

It seems to me to be a matter of luck that your rear wheels don't start sliding in an out. With everything in it's proper position, there is just enough room to fit the original thin paper gasket. This is thick enough to just prevent the halfshaft being permanently in contact with the planet gear pin. I have come to the rather bizarre conclusion that using a gasket thicker than the original increases the chance of the hubs starting to slide in an out. My brain had nowhere else to go, nothing else to cling to.

This post is a bit wordy, I know, but many are plagued by rear hub problems and I've not been able to find anything that goes into great detail. The tolerances seem to be very fine, and I reckon it's easy to get it all wrong.

But I don't know what "wrong" is. I don't know what "right" is. I don't know why a car has a a rear hub that depends solely on the tightness of the fit of the bearing inside it to prevent it sliding about. I'll not go into my thoughts regarding the O-ring, other than saying that when it's used the halfshaft is a "bouncy" kind of fit on the hub. Unless it's compressed flat enough for the hub and halfshaft flanges to mate together properly in full contact. Then it's waste of time having it there .

????

I...need....some....beer....

The rear hub nut and lock washer stops your rear wheels sliding in and out.

You are overthinking things!

chickenjohn wrote:The rear hub nut and lock washer stops your rear wheels sliding in and out.

You are overthinking things!

No it doesn't, and no I'm not.

I have an axle on which the hubs slide in and out. The nuts were extremely tight and the lockwashers perfectly bent up. So your comment is not true.

The questions are:

What causes the hubs to start sliding on the bearings?

Why do so many people have oil leaking into the brake drums from between the hub and the halfshaft flange?

What can be done to improve the situation?

A correctly-functioning rear brake system is of paramount importance. Braking efficiency is reduced when the shoes become contaminated with oil.

I spent four hours yesterday investigating this using two pairs of hubs I have. One pair had the original thin paper gaskets and were firm on the bearings, but the drums were wet. There was no sign that the oil was leaking past the hub oil seal. The other pair had thicker, home-make gaskets and the hubs were sliding about on their bearings, but the drums were dry. After four hours, I was unable to come to any concrete conclusion about how I should proceed in assembling the hubs on the axle I plan to use. Use the thin gaskets, and have hubs tight on the bearings but oil in the drums? Or use thicker gaskets and have dry drums but sliding hubs?

I've been doing cars for forty years, and it was unusual for me to spend four hours looking into something and then coming away none the wiser at all about how to proceeed. I read a comment here from someone who hasn't ever had problems with rear hubs, and he seemed to dismiss the whole thing as somewhat irrelevant and unimportant.

It isn't.

I don't have a Morris axle so I can only refer to the manual.
1) Hub and bearing assembly goes onto axle. (which is STEPPED for the hub/bearing to locate against)
2) Then washer/locknut is fitted.

And so, unless I've missed something, these components are attached and hub should spin but can not fall off.

3) Half-shaft is fitted, with the four wheel studs of the hub, poking through the holes on the half-shaft flange.

And so, once the wheel studs are fitted (and wheels), the half-shaft can't fall off either.

daveyl wrote:I don't have a Morris axle so I can only refer to the manual.
1) Hub and bearing assembly goes onto axle. (which is STEPPED for the hub/bearing to locate against)
2) Then washer/locknut is fitted.

And so, unless I've missed something, these components are attached and hub should spin but can not fall off.

3) Half-shaft is fitted, with the four wheel studs of the hub, poking through the holes on the half-shaft flange.

And so, once the wheel studs are fitted (and wheels), the half-shaft can't fall off either.

Yes, there is a step and the bearing locates against this, but the hub doesn't locate against anything. It is true that the hub cannot fall off because the large locknut prevents that. But there is nothing to stop the lateral inward movement of the hub once it starts sliding on its bearing. So here we had someone daily driving around in a Moggie but totally unaware that the back end was sliding about. There could be many more cars suffering from this issue without the owners being aware of it.

That's the weird thing - it's like it doesn't matter that half the wheels are not firmly fixed in position. You can't hear or feel anything untoward. The first thing you'd know of it is when the MOT guy rocked the wheel from side to side and determined the bearing was okay in that respect, but gave the traditional long intake of breath when he grabbed it and pushed it it and pulled it out, testing for lateral movement. I've had such a failure. I was surprised. I am none the wiser regarding the cause after all this mulling. It wasn't a one-off either. I have a total of five rear axles, and there are three instances of sliding hubs. That's about a third of them - one in three, hubs loose on their bearings! None of it anything to do with something I'd done....just as I bought them, either on cars or off.

So, statistically I suppose (and perhaps not to be taken too seriously on such a low sample), one in three Moggie owners has a car with a hub sliding about on its bearing.

But it must matter, surely? Wheels should not be floating about - they should remain in a fixed position on the axle.

I might add that the axle with the sliding hubs to which I refer came from a car (not mine) which had been in daily use until the engine siezed up because of a lubrication problem. I bought the axle complete because I wanted the spare parts (and the price was attractively very low).

Each hub is able to slide inwards towards the centre of the axle by about an eighth of an inch. I had nothing to do with this axle other than buying it and later giving it the once-over.

The point of the thread is: why do some hubs start to slide of their bearings, and some don't? What causes this? What could be done to prevent it happening, if anything? How long can a hub be sliding about on its bearing before things start to get dangerous somehow?

Further, why does oil leak between some hubs and halfshaft flanges, but not between others. I didn't start the thread to discuss whether the issue of sliding hubs exists - I know it does. I have axles on which the hubs slide in and out on their bearings. I have posted here about the same problem I had with a hub and bearing when trying get an MOT for a Morris I brought to Poland (great place for a football tournament !).

When I write "sliding on its bearing", I don't mean "the hub will move in and out if great forces are exerted upon it". I mean "the hub will slide in and out if pushed lightly with a finger when the hub is in place with the locknut and everything assembled as per the book".

Something I'd like to know - what pressure would be needed to insert a new bearing into a new hub?

Update....after a thought I had....

The width of the shiny area inside the brake drums which were on the axle to which I refer, which gets polished by the brake shoes, is wider than the brake shoes....by about an eighth of an inch.

Isn't this exciting ?

Seriously, try the push-pull check on your back wheels next time they're off the ground (obviously with the car on something much, much safer than a scissor jack). If you find any lateral movement, I have no idea what caused this. I know the reason for it, but not the cause of it.

I search enlightenment. My conclusion so far is this:

* The hub is tight on the bearing, and all is sweetness and light.

* Over time the bearing wears out to some degree - not enough to allow any wheel rock, but worn somewhat compared to its original condition.

* The wear reduces the tightness of the fit of the bearing in the hub.

* The hub starts to slide on the bearing.


What this would mean is:

Rear hub bearings can be worn and needing replacement before any wheel rock can be discerned.

That's the only thing that makes any sense to me on this matter.

It's a tricky one to deal with, because there are no preventive measures that can be taken. And no way of knowing when the sliding starts, other than doing a pyhsical push-pull check everyday. The best advice is to do the push-pull check every three months or so. It seems that a Morris can trundle on quite happily for a long time with sliding hubs without anything nasty happening.

Another thing I'd like to know is this:

Once a hub has started to slide on its bearing, would it mean that a new bearing would not be a tight fit in the hub, ie the hub's bearing face has been worn because of the sliding? Or would it need a prolonged period of sliding to wear down the bearing face in the hub? Or would the hub never wear because of the oil always present present between the bearing outer ring and the bearing face in the hub once the hubs start to slide (on the ones I inspected at least).

So, mainly, should the push-pull check be a more frequent part of the general maintenance and inspection routine? Safety doesn't seem to be an issue at all, although I cannot rule out the possibility of something going badly wrong eventually.

We're talking money here....a car shouldn't be given an MOT pass when a hub is sliding in and out.

I can assure you - rear hubs DO NOT slide in and out......... There's something wrong with the assembly if that happens.

bmcecosse wrote:I can assure you - rear hubs DO NOT slide in and out......... There's something wrong with the assembly if that happens.

Yes, obviously something wrong the assembly, but what? And why? I'm not sure actually if you mean something wrong with the assembled unit, or the way in which the components were assembled.

Take it from me, hubs CAN slide in and out.


Anyway, I've not posted this thread to argue about whether this happens or not. The three replies so far have been rather dismissive, so I'll stop posting.

So much for discussion and debate.

Totally irritating in fact....I spend time sharing information about issues I've experienced with a Moggie, and all I get told is that it can't happen.

What? I'm making it up?

No. It can happen. What esle explains the fact that the polished area in the brake drum is wider than the shoe by the same amount of the lateral slide? Maybe one needs to post up photographs here to prove that one isn't lying. But I could shave a brake shoe with a grinder to deceive everyone. How cunning!

Perhaps it just irks regulars here to read about issues regarding a Morris Minor of which they have no experience? I expected some discussion, not to be told that "It can't happen".

Morris Minor rear hubs can slide in and out. There have been posts here about it. Someone suggested the sliding action caused oil to be pumped past the hub/halfshaft seal. I have no views on this.

Bye.

YOUR hubs appear to slide - mine certainly do not. Perhaps you have incorrect bearings in the hub . I don't have a handy spare axle to play with to decide what could be wrong with yours....... Be huffy if you wish - but at the moment I don't have time (or to be frank, after your comments, the inclination) to investigate further.

mine did this. i could turn the bearing around in the hub with 2 fingers. the cure was another hub and bearing.

how i think mine ended up like that was that it was pulled out from under a tree after 30 years and had seized. rotation of the wheel must of had the bearing turning in the hub as the wheels moved.

since i have fitted hubs with the rubber ring from a wolsey 1500 (i think), i've had no more leaks.

Hi,

Can only think that from the symptoms you describe the cause can only be that at some time the bearing has been replaced but not pressed in squarely, this then has shaved off some of the bearing surface on the hub. Over time with the forces exerted on the hub the bearing starts to spin in the hub and allows oil past a worn oil seal and gets on the shoes.

The bearing should be an interferance fit into the hub, once in correctlly its then down to the nut to hold the complete hub in place.

Richard

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I generally prefer Mr Gordon's excellent product -with a splash of tonic and a nice slice of Lime......

When I changed my hub bearings, seals and gaskets ( oil in the drums) one hub had its previous bearing "fixed" kind of welded into place, not welded but VERY tightly bonded, I assumed a factory fit from 1965. However removing this remaining metal ring (I dissolved the rubber portion with acetone) proved impossible for me to do so I found a spare hub and put a new bearing into it. If I HAD managed to remove the original "fixed" Bearing then the new bearing would have space to rock inside the hub, or the hub move away from the bearing as you suggest. I still have no firm idea why one hub had a press fit bearing and one a "fixed" bearing. As to fitting new bearings.... Wrap the new bearing in 2 layers of freezer bags, pop in the freezer overnight. In the morning put your hub in a moderate oven then have a brew (2 if its cold or raining) take the frozen bearing and introduce it to the warm hub and it will plop in with NO pressure,drifts or stress.

Rob Thomas wrote
the guaranteed ugliness of Korean cars. ......................


I must disagree

For goodness sake.....clearly the inner surface of the hub has worn which is allowing the bearing to move inside the hub. Simples. I had a front hub/drum on my Series II which suffered the same problem due to a bearing seizing at some stage and spinning round inside the hub.

.

The bearing is not a particularly tight fit in the hub - it doesn't need to be (but feel free to use Bearing Loc if worried..) . The sliding in-out will be entirely due to width of bearing V width of housing in the hub. So either the bearing is not wide enough or the hub has worn. I can only see that happening if the axle is run with the big nut not tight enough......

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