Rear axle and bearing and oil seal gap.

[Sarge]

More to the point, should there be one ?

Pulling my hair out with oil leak along half shaft and onto rear brakes.

Oil seal changed, bearing changed while at it. Confirmed correct orientation of oil seal from numerous sources !
New rear hub gasket and big rubber "O ring"

In the pictures you can see into the hub and the space between the bearing and oil seal, with an allan key pointing out the gap.

Any words if wisdom would be appreciated.[frame][/frame]

pointing out the gap :[frame][/frame]

From the other side, bearing is flush with the hub face, is this correct ?[frame][/frame]

[alexmcguffie]

Is the mating face on the axle that the seal runs against nice and smooth with no rust, marks, etc? Did you trial fit the seal on the axle mating face? I guess you are sure its leaking from the oil seal and not the paper gasket?

[bmcecosse]

The bearing should actually protrude by 4 thou - the thickness of the paper gasket. I think it looks fine from that picture. Is the axle overfilled? Is the breather clear? And -check the little drain hole in the backplate shroud is clear - although oil shouldn't really be getting there anyway - but if it does the drain should prevent it getting to the shoes.

[John Naylor]

If there is wear on the surface the seal runs against, the seal can be positioned just away from it. But check for overfilled axle, blocked breather and ensure backplate drain hole clear....

[philthehill]

Are you absolutely sure that the hub seal has been fitted the right way round? I may be wrong but from what I can see and comparing the seal orientation with a NOS seal I have in front of me it looks as if the seal has been fitted wrong way round.
The seal should be fitted with the seal details towards the rear of the hub as per attached photo and with the lip seal spring towards the bearing:-[frame][/frame]
[frame][/frame]

[bmcecosse]

Is the seal designed to rub on the half shaft Phil ? Surely it rubs on the machined surface of the axle casing... But you are right that it could be wrong way round - hard to see.. The axle casing can develop a worn ridge where the seal runs - and as mentioned earlier - the seal can maybe be repositioned so the lip avoids that ridge. There are also thin sleeves sold (Speedi Sleeve is one...) to slip over the wear area and present a new surface to the seal.

[Sarge]

Wow, thanks as ever loads of great info and ideas. I'll get to work in daylight hours !

[philthehill]

bmc
The seal does indeed rub on the axle casing - the attached diagram was only for illustration and to show which way the seal fits in the hub.
If there is a slight wear ridge on the axle casing it may be removed with a very fine wet stone soaked in WD40. Use the wet stone radially around the axle casing and not along the axle casing. Make sure any abrasive/metal is removed before fitting the hub and seal.
Phil

[bmcecosse]

I know you know Phil - it was just to clarify... You may be able to get a 'double lip' seal at the same size. which would be better - sorry - I don't know the size of that seal - it's not an area that has ever given me any problems !

[philthehill]

This is the information moulded on the Minor rear hub seal:-

NAK - SC - 1.750 - 2.500 - 0.375

Measuring the seal:-
ID = 1.750" when fitted (1 & 11/16" measured unfitted)
OD = 2.500"
Depth of seal = 0.375" (5/16" measured)

It may be of use in trying to get a double lip seal.

[bmcecosse]

So - that's ID / OD / and thickness. May be tricky since most seals are metric these days....
Edit - well -it's in USA -but it exists ! https://worldindustrial.com/p-17253tc-1 ... 8AOE4.dpbs

[philthehill]

bmc
Thanks for finding that.
Now added to My Favourites.
Phil

[BLOWNMM]

G'day to all
This is my first posting and is made in an endeavour to clarify some rear hub assembly problems.
http://morrisminorowners.co.uk/viewtopi ... =14&t=9310
Would like to bring to your attention a case of rear axle failure. There are parts suppliers here and in the UK supplying rear hub gaskets which are up to 0.035 inch (0.89 mm.) thick. In the Minor workshop manual, the rear axle section page HH5 it is clearly stated that the hub bearing should protrude beyond the face of the hub AND paper washer by .001 to .004 inch (.025 - .102 mm.) with the bearing fully pressed into the hub. This assures that the bearing is gripped between the abutment shoulder in the hub and the driving flange of the axle shaft. Using a gasket of the thickness of those being supplied goes nowhere near allowing the clamping the outer race of the bearing as required, and this would allow the outer race to move around and cause flexing between the axle and its driving flange, probably leading to failure as depicted in the link supplied. Although it cannot be shown that the failures indicated in the link were associated with the bearing not being clamped I know where I would be placing blame for these failures, especially as in the case of the breakage a new quality bearing was fitted which had only travelled 5000 miles. If when the new bearing was fitted the gasket used was from the usual supplier then it would be reasonable to attribute the failure to the bearing not being clamped. There seems to be no definitive thickness to the gasket that I was able to find but there are several references to 0.008 inch. My approach would be to make the gasket thickness as required to meet the specification of the bearing protruding by .001 to .004 inch from both the hub AND gasket. It should be noted that if the bearing is clamped between the hub and and the axle flange the the gasket is thinner than the gap, by between .001 and .004 inch which would possibly allow oil leakage. In other words the gasket would not be providing proper sealing. I suspect that this was the reason for later modifying the hub to have an O ring for positive sealing. If the gasket sealing remains a problem it can be easily overcome by fitting 6207 2RS bearings as well as the normal seal fitted to the hub. The 2RS means that they have 2 rubber (actually nitrile) lip seals, and are charged with a good quality grease which is meant to last for the design life of the bearing. Because of the fitment of lip seals on both sides they will not let anything enter the bearing including diff oil. I will be removing my axle shafts and carefully checking this bearing protrusion. There is one benefit of such a failure that being the shaft is easily removed and the diff centre does not have to be removed for cleaning out swarf, not that such a failure is welcome.
Cheers Bob

[bmcecosse]

2RS doesn't mean 'two lip seals' it means 2 rubber shields on the side of the bearing... Not necessarily a good thing here since the bearing relies on oil for lubrication. The bearing should protrude 4 thou above the flange ONLY - and the correct 4 thou gasket will then seal that gap nicely and clamp the bearing. This is all well known... Yes - the thick gaskets are a complete nonsense - made and sold by firms who just don't appreciate what's going on. BMC in their wisdom saw that with tolerances the gasket wasn't always doing the job on early cars - and added the very essential rubber O ring to ensure oil retention - especially when the wheel nuts are loosened off.

[BLOWNMM]

Hi all
The Morris shop manual on page HH5 specifically states 'the outer face of the bearing should protude beyond 'THE FACE OF THE HUB AND THE PAPER WASHER' from .001 to .004 in. not 'JUST THE FLANGE ONLY'. 2RS bearings do have a lip seals on both sides and are lubricated at the factory when made and the lubricant is designed to last for the design life of the bearing. They do not need to rely on oil from the diff. If you refer to the attached link it will explain this..bearing-warehouse.com/6207_2RS_p/6207-2rs.htm

Cheers Bob

[BLOWNMM]

Hi all
The link I posted did not work. I will try again.http://www.bearing-warehouse.com/6207_2 ... 07-2rs.htm
Cheers Bob

[bmcecosse]

If that was so -then a 4 thou gasket won't ever seal..... despite the hallowed Manual - it is 4 thou above the flange... use grease bearings if you will - but that's not the design.

[BLOWNMM]

G'day Roy
The design for the hub bearing was for a 6207 bearing obviously with adequate lubrication. What better lubrication could you wish for other than a properly sealed 6207 bearing, charged at the factory with grease to last for the design life of the bearing, rather than relying on occasional lubrication to a fully open bearing from possibly contaminated oil from a diff, which may contain particulates ie. metal particles from normal wear and tear and especially swarf from diff centres having experienced an axle failure releasing this crapp due to the axle casing not having being cleaned out properly. The added advantage is that the bearing being sealed, does not allow diff oil to pass through it and cause potential leakage problems.

Cheers Bob

[bmcecosse]

It's shocking really....but in all my years of Minoring I've never had the slightest problem with rear (or front come to think of it) bearings! I must have been extremely lucky!!

[philthehill]

With a sealed bearing fitted into a Minor rear hub what are you going to do with the hub seal?
The seal does rely on a small amount of oil to lubricate the lip on its way around the axle casing. If there is no oil the seal will overheat and fail.
The seal must be fitted and lubricated whatever bearings are fitted even if it is only grease between the bearing and seal.
I have never experienced a half-shaft fail like that above but I have had original BMC rear hub bearings start to become noisy and they were then changed before total failure or causing the seal to fail.
The original half-shafts and bearings in my Minor did over 80k before I uprated the axle half-shafts so as to be able to transmit 178bhp max but they are still original spec hub bearings and they have been subjected to far more load than any standard Minor rear hub bearing would be subject to especially with over 135bhp from the engine and with 7J very sticky slicks all round they have been perfectly ok but the oil in the rear axle is changed at regular intervals.
As regards metal particles inside the axle casing - if you have an axle shaft fail it is an absolutely imperative to ensure that the axle casing is completely cleaned out to remove all traces of crud.