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#1 Replacing rear diff output oil seal

Posted: Sat Nov 18, 2023 6:31 pm
by RICHOT
Hi guys,
Just noticed that one of my rear disc brake discs has an oily deposit on it on the inside - suppose itโ€™s from the output seal leaking.
My question is: is it possible to replace the oil seal without going through the hassle of taking the whole IRS down? (Which I have done on several occasions in the past but am getting a bit old for that now!).

It looks and seems possible.

Have any of you had experience in doing/trying this ?

Thanks,

Richard

#2 Re: Replacing rear diff output oil seal

Posted: Sat Nov 18, 2023 7:46 pm
by mgcjag
Im sure its doable but a struggle....so make it easy....Just drop the irs it will be far easier in the long run....read all the other threads it may not just be the seal could even be a worn shaft...so speedi sleeve is an easy option....while its our you can do both sides....Steve

#3 Re: Replacing rear diff output oil seal

Posted: Sat Nov 18, 2023 9:13 pm
by rfs1957
A note of caution which may or may not be relevant, but which others might stumble across when searching for threads about diff leaks.

I thought I had leaks from BOTH my rear seals, both sides, judging from the projections on the (white) undersides of the boot.

Two at once did seem very unlikely.

I wondered if I had failed to install them correctly, or if there had been a bad batch of seals, and I pulled both bearing blocks out - yes, with the IRS out - and ordered two new seals from Alan Slawson, reckoning that he must know what works.

Image

I fitted the whole lot back together none the wiser really, but FORTUNATELY when rotating the IRS on the jig I use, in one of the many positions it adopted during caliper fitting, re-doing brake pipes etc etc - all of a sudden there appeared a drip.

And the diff actually had almost no oil in it at this point.

It turns out that it was the cover-plate sealing that was defective - somewhere higher than the natural oil-level - and I now think that as it must get very windy/breezy around that area of the car, a leak from the cover plate can actually get blown onto the discs in a way that would make you suspect it was an output seal.

It would have helped me to know this before completely dismantling the output shafts ........

#4 Re: Replacing rear diff output oil seal

Posted: Sun Nov 19, 2023 1:41 am
by mtnjag
My retired British car mechanic friend, and a former Jaguar dealership mechanic I know who now has an independent garage both do the output seals without removing the rear suspension,

However, itโ€™s done on a lift. You must have the car up in the air.
No lift, pull the IRS.

#5 Re: Replacing rear diff output oil seal

Posted: Sun Nov 19, 2023 2:14 am
by abowie
The hub is behind the brake disc, which in turn can't be removed without removing the brake calipers.

I put an IRS together once without fitting the discs and calipers and had to strip it down and take the pumpkin out to rectify this.

Bolting the calipers on with the pumpkin out of the frame is hard enough. You're supposed to safety wire the bolts but I ended up using Loctite because this was too hard even with the pumpkin out. I'm not sure how you'd access the hubs to replace the seals in this situation.

#6 Re: Replacing rear diff output oil seal

Posted: Sun Nov 19, 2023 7:51 am
by rfs1957
I hope you'll put a full account of this up with pictures if you manage to do it.

Like Andrew, I always find the caliper / caliper mounting plate / disc business extremely tricky, never mind the requisite lock wiring, even when I've got access from all angles with the IRS out and rotating on a waist height jig.

Good luck and hope you prove us wrong ๐Ÿ˜œ

#7 Re: Replacing rear diff output oil seal

Posted: Sun Nov 19, 2023 9:33 am
by RICHOT
Hi guys,

Thanks for all your comments and suggestions.

Looks like Iโ€™ll have to bite the bullet and take the irs out - Iโ€™ve done it several times over the past 30years but at 78 it will be quite a task!

Itโ€™s either that, or pay someone to do it!

Think Iโ€™ll try again myself๐Ÿ‘๐Ÿคž๐Ÿ‘.

Cheers and happy motoring๐Ÿ‘.

Richard