Diff Seals

[nigelj77]

my '98 450 is suffering from a slight leak from the rear diff, looks like the seals which the output shafts pass through, has anybody on here changed them, how hard are they to get at and are any special tools required to remove them?

Thanks in advance.

Nigel

[TJC46]

nigelj77 said:

my '98 450 is suffering from a slight leak from the rear diff, looks like the seals which the output shafts pass through, has anybody on here changed them, how hard are they to get at and are any special tools required to remove them?

Thanks in advance.

Nigel

The output shafts have an aluminium collar which screws into the diff casing. These can be a basard to undo because of corrosion between the 2 dissimilar metals, i.e. aluminium and steel.

There is a special tool to help removal, but that is no guarantee they will come undone.


Question is why is the seal leaking? Maybe time to rebuild the diff, new bearings and seals, and fresh oil.

Best bet is to ring John Reid at Grantura engineering in Blackpool and have a chat with him.

He recently rebuilt my diff and is work is 2nd to none.

For all the work that is involved in removing the diff, its worthwhile having it rebuilt. You can also change the diff bushes for poly ones. With the diff out, the dreaded top bush is a lot easier to remove.

If you remove the diff yourself then the rebuild cost is circa £400 to £450 plus carriage charge.
Im only 60 miles or so away from Blackpool, so i delivered/collected myself.

[nigelj77]

Oh dear, that doesn't sound good, I was assuming it was just that the seals had hardened or worn with old age, the car has done 52K miles and diff makes no excessive noise it's just dropping the od bit of oil and as it's dripping out onto the stub axles is getting sprayed around the back of the car.

Hope I don't end up having to drop the diff out to get the seals done, I was hoping I could just get the seals changed in situ.

[TJC46]

I dont know for sure if the seals can be changed in situ, but i would say not.

My diff was leaking slightly from the propshaft seal, and i dropped the diff and took it to to have just the seals changed. This wasnt with Grantura engineering, but was with a gearbox/diff specalist.

The propshaft flange was easily undone, but the 2 output shaft aluminium collars, which have to be removed, were seized solid. So much so that even when some serious heat was applied, they would not budge.
Bear in mind this is off the car with the diff held and fixed by a press, so no access problems, but they were seized solid!

I was fortunate to have a spare diff, that needed a rebuild, so it was this one that, John at Grantura engineering rebuilt for me.
My original diff was now useless as the heat had destroyed the oil seals, and i gave this to John as part of my rebuild cost.

He will probably destroy the 2 seized aluminium collars to get them out.
He does carry stocks of new ones, and in hindsight, i wish i had gone to him in the first place.

It seems you have 2 options:
To put up with the slight leak if its only tiny....or
To drop the diff. You could just get the seals changed, [if the collars come undone]but for what that would cost, you may as well cough up a bit more cash and have a full refurb.

[ChimpOnGas]

Put some stop leak in it and you may get lucky.

Your breather may also be partially blocked creating an overpressure situation causing the leak.

Two cheap things worth trying before you heave the diff out.

Edited by ChimpOnGas on Sunday 6th April 21:30

[nigelj77]

So I've got the "stop leak" and am going to try and add it this weekend, the bottle says treats 5lt, my research says the diff takes 2lt, question is do I add the full bottle or just half????