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