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MG Midget and Sprite Technical - Axle oil seal gasket - totally confused

Rear axle up on stands in shed and I'm just about to put new oil seals in while it is off after major repair to casing (another story).
Opened the pack from Fast Track Bearings containing 2X midget 1275 rear axle oil seal and gasket. Seals look fine, but I'm surprised to find that the two gaskets are the big eight-hole jobs for the banjo. I was expecting to find much smaller gaskets to go in front of the seals. Banjo hardly leaks so I wasn't planning on taking that apart. Having checked the archive on pinion oil seal fitting it seems that if you don't change the gaskets, it will still leak (unless the breather is blocked which creates leaks anyway).
I didn't have any real leak problems. One seal was changed for MoT last year but I thought I might as well put a new one in other side while axle is off.
Can I just bung one in without a gasket, or using gasket goo of some kind?
I can't think that the banjo gaskets have any effect on the pinion oil seals, so what are the gaskets that previous threads tell me I must fit? The Moss catalogue (can't find my Haynes) doesn't show a gasket next to oil seal.
Any help much appreciated.
C Whiting

I think you may be referring to the half shaft gaskets. I've had them leak oil into the brake when reusing old ones. New ones would be best, or silicon would probably do the job.
Dave
D Spencer

I don't think the ones I have are half shaft gaskets - they are completely circular, measure 20cms edge to edge and have eight bolt holes.
It would certainly make more sense to have gaskets for the half shafts, but I had assumed that "rear axle oil seal with gasket" would be the bits I needed.
I think I had better go back and find a pair of half shaft gaskets and give up on this planned rainy day project and wait until I have the right bits - be a shame to get the thing back on and find it leaks (especially when it didn't before!)
Thanks for the advice.
C Whiting

>>The Moss catalogue..... doesn't show a gasket next to oil seal.<<

http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=11636

you need #s 53, 54 and 55.
That's the trouble with buying 'kits' - which very often are not put together by anyone who's worked on or even owned one of the cars they're meant for. They often don't contain all the bits you require, yet include stuff you don't need. I avoid the word like the plague...
David Smith

Oh dear. I was already looking at my Moss catalogue and getting thoroughly confused. Looks as if I might have the wrong part altogether. The rear axle pinion oilseal I have in front of me doesn't look much like Moss part 53, which appears to be a bearing rather than a seal, and is marked "oil seal rear hub bearing.
The one I have (I actually have three now, because I had one fitted to sort a leak into the brake drum at MOT last year, and have just found a box of bits left over from the job containing the other half of the pair)is a grey/black hard rubber disc with an inner spring around an inner lip to grip tight. Nothing like Moss part 53 and actually looks more like part 30, which is marked "oil seal". But if that is the case, how come the one fitted for MOT last year sorted the leak into the drum?
I have added a picture.
I don't need any new bearings as far as I can tell. The half shaft had to come out for the axle case to be repaired and I want to make sure it is oil tight when I bolt it all back together.
I'm sure it makes no difference, but the car is a Healey Frogeye. The factory seems to have fitted wire wheels using a steel wheel drive shaft assembly as normal practice, so they are not standard MG/AH wheels.
As the thing wasn't leaking before it came apart and the seal hasn't been disturbed apart from having the shaft pulled through it, I might be better simply replacing the gasket (Moss 54) and forgetting about the seals - or might pulling the shaft through have disturbed the O ring?


C Whiting

I have no idea why you are confused except that you may be unfamiliar with your Sprite, and car mechanics in general?
Firstly you mention 'pinion oil seal' - the pinion is the input shaft in the nose of the diff, nothing to do with halfshafts; having re-read your posts I'm convinced you are refitting a halfshaft, yes?
In which case follow the link I gave before, you want 53, 54 and 55. Cross-refer the diagram to the part description in the list below, oil seal, gasket and O-ring respectively. (FWIW 52 is the bearing.)
You have to remove the hub from the axle casing to change the oil seal.
The O-ring and gasket fit on the outside face of the hub, O-ring first - it sits in a groove - then gasket, then halfshaft.
David Smith

Thanks for that - No, I haven't taken an axle apart yet and my mistake was to order an "axle oil seal" without first dismantling the thing to see what the part actually looks like. I clearly have the seal for the input shaft in the diff.
The garage which fixed the oil leak into the brake shoes last year gave me back one identical to this as part of pair they had ordered - and the hub no longer leaks - but I now suspect they ordered the wrong part themselves and probably used gasket compound to solve the problem.
Off to order 53, 54 and 55 from Moss.
Thanks again.
C Whiting

"and actually looks more like part 30, which is marked "oil seal". But if that is the case, how come the one fitted for MOT last year sorted the leak into the drum?"

The reason changing that oil seal sorted the leak, was because axle oil was escaping past that seal and running down the inside of the brake back plate, onto the drum and then being spread all around, depending on how much of a leak there was.

These oil seals last an age. Usually you don't need to replace them, when changing the hub bearing. But if you do have to change the hub oil seal, then you have to remove the bearing as well.

Removing the bearing is easy enough, but the oil seal will probably have been in there for a long time, and won't want to come out easily.

As it happens, I changed a leaking oil seal in one of my rear hubs today. I had to practically destroy the oil seal to get it out, which didn't matter other than the hastle factor and slowed me down.

So your best bet, if you previously had no leaks, is to put it back together again.

No, the halfshaft doesn't run in the oil seal. The oil seal spins around on the axle casing. The halfshaft passes through the axle casing. So you won't have disturbed the oil seal at all.
Lawrence Slater

Few! I thought for a moment someone would mention undoing the hub nut....
Pete Ottewell

As it happens Pete :).
I almost forgot that I took a picture today of my trusty wrench on my nut. lol.



Lawrence Slater

Brilliant! Many thanks Lawrence. As it wasn't leaking before the axle casing fractured (see Alan Anstead's forthcoming piece in Mascot regarding that) I think I'll just replace the half shaft gasket and forget all about O-ring, bearing and seal. And if it does leak, I'll know where to start.
C Whiting

If your replacing the halfshaft gasket, you might as well replace the O ring too. They do last a long time, but the O rings are so cheap you might as well replace it while your at it.
Lawrence Slater

I now don't bother with the gasket as I have had better results with the o-ring on its own (more nip on it by the thickness of the omitted gasket) and no goo either. I was led to this conclusion after considering the number and range of applications where modern cars rely entirely on o-rings for a seal. Water pumps are an example.
Though to be belts and braces for our competition cars I go up a size in o-ring section.

Paul Walbran

How I do get the half shaft oil tight:
-I always put some silicon on the gasket (photo)
-If I give pressure on the half shafts while the silicone gasket is drying. Not only with the screw but also with the wheel nut under witch I do place an oversize nut (photo)
-I use the oil tight bearings:
long long ago Growler, South wrote:
And I shall start raving about fully-sealed bearings (you know, the pre-lubed type with integral oil seals)
They're lovely. Last forever and supplement the existing oil seal- no more leaks, and no more damaged bearings from differential metal flakes.
SKF part# 6207zz or NSK part# 6207vvc-mav2

Flip


Flip Brühl 948 frog 59

clean the haft shaft


Flip Brühl 948 frog 59

here you see how I mount a new stud but the principle is the same: oversized nut under the wheel nut

Flip


Flip Brühl

Personally, I'm not a fan of smothering stuff in goo, when it's not needed, because you only have to clean it off again later. I've never suffered leaks from the halfshafts when using a decent gasket and 0-ring. The thing is to make sure the surfaces are clean prior to assembly. and don't re-use the paper gasket too often, although it's surprising how long it lasts.

Paul,
I think the paper gaskets supplied today, are a little bigger than they used to be. They used to sit on top of the o-ring, and when you took them off, you could cleary see the indentation of the 0-ring in the paper. But the one I installed yesterday, sat just around the outside of it, so I take your point about not using it at all. The o-ring will be compressed more without the gasket. Never occured to me to do that. But how about corrosion on the axle and shaft mating surfaces? Without the gasket, won't there be more chance of water getting between and rusting the surfaces?
Lawrence Slater

The Bentley manual states that the gasket must be at least 0.010" thick, but does not elaborate why. I recall a past discussion about this in the archives here (in which several stated they've not used a gasket for years and had no issues).

I am trying to remember whether the presence or not of that gasket would have any impact on the alignment of the hub bearing or anything else.

Because the half shaft is floating at the diff end, then it shouldn't care either way.

Norm
Norm Kerr

I think this sketch is correct (working from memory during lunch, at work!):

blue = half shaft & wire wheel hub

green = rear axle housing

red = hub bearing

purplish/pink = rear hub

orange = brake back plate and drum

it seems to me that whether the gasket was there or not (the thin line between the blue half shaft and the purple hub), the only difference would be the amount of compression of the o ring, and the half shaft position shifted to the left by 0.010". The bearing wouldn't care either way, right?


Norm


Norm Kerr

Lawrence
Yes, I noticed that difference in gasket design too.
Corrosion hasn't been an issue. But then again, we don't have salt on our roads here.
However, to get in to that area the water has to get past the brake drum first, and I haven't seen a lot of evidence of it being in the brakes. Condensation if a car isn't used much, yes - but there's a very good cure to that!
I don't think corrosion there would be anywhere near as much of an issue as immediately outside of the wheel bearing seals, either front or rear.

To me, if an equivalent situation was being developed now in a modern car, my bet is that the makers would rely entirely on the o-ring.

Norm
I agree, I can't see any difference for the bearing.
Paul Walbran

Calling Paul Walbran!

Paul, I too have been experiencing oil in my rear drums & I'm preparing to replace the bearings & seals.

Since there seems to be some inconsistencies with the paper gaskets currently available I was considering following your approach & going paperless.

Do you still see this as the way to go?

If so I like your belt & braces idea of an oversized O-ring. Can you suggest dimensions, part number or supplier where I can source these in the UK?

Or for a few bucks can you ship some from NZ?

Many thanks

Paul C.
P R Clark

The hub bearing is clamped between the hub and the halfshaft.

The correct thickness gasket provides for the correct clamping of the bearing when everything is bolted up tight.
Dave O'Neill 2

I found some larger cross section o rings at my local hardware store. I don't remember the diameter of the hub as I brought a hub with me but the cross section was .125.
J Bubela

This thread was discussed between 04/06/2012 and 09/09/2015

MG Midget and Sprite Technical index

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