Morris Minor Owners Club

Another problem on my new moggy. Pool of oil this morning, but only small, under the differential. It look like it is coming from the prop shaft entry point, so looking at the moss diagram Im guessing the oil seal has gone in there. So what I want to know I spose is if this is easy to change. The digram seems to be saying it is.

Do you just take the propshaft off, undue the big nut, pull off the washer, dustseal and stuff and then replace the oil seal and put it all back together without having to take the differential off, is that about right?

Should I replace the dustseal and bearing at the same time?

Also on ESM the oil seal that looks the same is called a 'pinion' seal, is that what im after?

Hope somebody can help cos Id really like to do it myself.

The problem is the 'undoing' of the nut - which should be extremely tight. And then of course - it must be tightened 'extremely' tight again.

Oh right, can somebody do that at home with normal spanners and such? Or should the differential be taken off and taken somewhere. When you say tight, to what torque setting should it be?

It is VERY tight - 140lb/ft and needs a good quality socket and torque wrench to ensure correct pressure and no damage to the pinion nut. Most of us live with some leakage at this point and even a new or reconditioned unit tends to leak a bit. See this thread also - http://www.mmoc.org.uk/viewtopic.php?f= ... ut#p421865

The difficulty I guess for most of us is keeping the diff steady enough to apply that much torque to the nut. I think I would just look for a replacement diff and perhaps have the original one reconditioned for replacing in the car at some later stage.

There was a thread on this last fall:
http://www.mmoc.org.uk/viewtopic.php?f= ... ut#p397040
Some good tips in there for the novice.

Thanks Katy, I'll try that. Do I only need to order a replacement seal then, nothing else?

Need to find some angle iron

Certainly keep the diff IN the car - otherwise hard to hold it down. You may find the nut is loose.....

Ha - that's what I'm hoping for!

Aye - but you still have to tighten it up properly.... Honestly - I do suggest you just live with the oil leak as long as it's only a drip or two. Is the underside of the car - in line with the nose of the final drive - soaking wet with oil spray?

Leak? ... that's not a leak .. it's a 'healthy throughput of oil'

No, but it hasnt been used enough for that. But there is a puddle now of oil just from sitting about 1 and a half foot by one foot after only four days and this is going to be a daily use car, so it is more than just a few drops really. If I can't do it tight enough then it might be a replacement diff, but for 3 quid for a new seal I might as well try.

Check that it is oil from the diff and not brake fluid from the 3 way connector bolted to the diff

For the amount it would cost I'd have a garage do it unless you know what you're doing yourself. The diff isn't like the engine where you can just pop the bonnet and put half a pint in. With the smaller capacity of the diff there is the real risk it could run dry if you go on a long journey... you need ramps to fill the diff.

It is bad policy to run a defective car.

That's a BIG leak and yes it needs fixing, but I'm not sure just a new seal is going to do it...........

Ramps to fill the diff? I usually just crawl under and fill it? Don't even need to jack it... but I am very thin teehee.

Why BMC? Surely it is only the seal that holds the oil in?

Yes - but the fact THAT amount of oil is escaping suggests to me that there must be bearing problems to cause that much damage to the seal. However - I am a terrible pessimist, and likely it will just be a loose nut and leaking seal........ certainly worth checking - but if you do happen to find a spare final drive at a good price - I suggest you take it in stock!

What would be a good price?

£10 would be good......but I think last time I sold a final drive, I got £25 for it.

Jane,
I would have a go at replacing the seal even if only for the challenge. It's certainly worth a try. You'll need a 1 1/8" socket for the pinion nut with a long extension on the ratchet. If you have access to a pit it would be easier.
Regards
Declan