differential leak

[Olivier]

Just saw a leak at the side of the differential... Ordered 2 seal from mercedes
Mercedes were quoting me 7 hours work as you need to take the differential out as there is a wee clip holding the shaft inside, silly design...
Can I get away with leaving the diff in place and work it out from the back ,or this is a no go?
Anyone could guide me on an easy way to do it?
Cheers.
Olivier

 

[Adam230K]

LOL 7 HOURS!!!

It too me and a friend of mine that long to change the diff and the clutch!! and we're definately not mechanics!

Its never going to be easy if you dont have enough space, but removing the diff isn't hard, its quite intuitive.

How badly was it leaking?

 

[Olivier]

I am not sure how bad it is, it doesn't look too bad but one side of the diff is quiete wet/ dirty, this might mean I loss all the oil too
Yep, I thought 7 hours labor is a bit too much indeed especially when they know what they are doing.

 

[Olivier]

bad picture taken with the phone

here is the leak

 

[lynall]

Thats not a a leak tech terminology is a weep and a weep doesnt get fixed ever, just the level checked and adjusted as required bet you oil level is okay or just below the filler hole, mine has a worse stain than that and i wouldnt consider changing the seals, probably do more harm than good once unit is disturbed.



Lynall

 

[Olivier]

I was actually worry about moving it as there are 3 seals, and once you move the thingy, all are going to be disturbed, no, not like me
Really you think its OK? I'll check the oil level and see before getting into a mad work in the street

 

[Adam230K]

i agree with lynal, thats not a leak. If your diff lost all its oil it would be making a hell of a noise.

 

[Olivier]

Anyway, would it be better for a peace of mind to replace the seals?

 

[BlackC55]

I would call that a leak. The amount of built up dirt on it is a clear indication of a leak that has been there a while and there is an obvious drip. Drip=problem

The seals should only be replaced by a professional. The diff has to be removed and the back plate has to come off and the side shaftes have to come out by removing a little clip. This clip is tricky to re locate when re-fitting. The seal fitting has to be done 100% accurately. This can be easily be messed up as it is quite a delicate job.

The input shaft seal is tricky too as the diff preload has to be set after fitting.

 

[BlackC55]

It is a long winded job and 5-7 hours is the correct labour time.

 

[BlackC55]

LOL 7 HOURS!!!

It too me and a friend of mine that long to change the diff and the clutch!! and we're definately not mechanics!

Its never going to be easy if you dont have enough space, but removing the diff isn't hard, its quite intuitive.

How badly was it leaking?

Ha ha!

 

[Olivier]

Can you explain this a bit better please
The input shaft seal is tricky too as the diff preload has to be set after fitting.
Look to me like this is bad news...
There is quiete a bit of oil/ dirt indeed, not sure what is left in the reservoir?

 

[BlackC55]

The input seal is the seal where the input drive is. It looks dry in that area in the pic so leave it alone.

 

[Adam230K]

Olly must be right (he is a pro afterall), but to clarify, when i said i dont think thats a leak i meant it doesn't look that severe, i had that type of leak on my old diff for a year before i changed it and it still worked.

 

[Olivier]

I'll got some oil later today and top it up, we'll see how much is missing,then this weekend at the back road, I'll see if I can take the bugger off. Once off it'll be easier ish to change the seal.
Thanks to Olly for the hint and the black seal I need for the back plate.

 

[Will]

Just out of curiousity, what's the lowdown on these leaking diffs? Is it a design fault, poor quality seals or something?

It seems to be a common MB trait, from the old days up until fairly recently. Almost all cars a few years old seem to have a weepy diff! I think almost/all every MB I've ever owned has seemed to shown some sort of signs.

I guess so long as the leak/weep isn't significant and the level is kept correct it shouldn't be a major concern. Depends on how severe the leak is, the value of the car and how fussy the owner is.

Probably the pictured leak here is worse than average, and I guess if you're doing a fair mileage and not checking the level regularly you could run into trouble.

FWIW, my 2.5-16 had it's diff seals replaced on a major (£3/4k) M-B service some while back. Still looks slightly oily/grubby but it never leaks a drip of oil on the floor or anywhere and the level seems to be fine so I assume it's just an accumulation of dirt/oil film that wasn't cleaned thoroughly at the time?

If the level was low I'd be concerned though!

Will

 

[Adam230K]

Just out of curiousity, what's the lowdown on these leaking diffs? Is it a design fault, poor quality seals or something?

It seems to be a common MB trait, from the old days up until fairly recently. Almost all cars a few years old seem to have a weepy diff! I think almost/all every MB I've ever owned has seemed to shown some sort of signs.

I guess so long as the leak/weep isn't significant and the level is kept correct it shouldn't be a major concern. Depends on how severe the leak is, the value of the car and how fussy the owner is.

Probably the pictured leak here is worse than average, and I guess if you're doing a fair mileage and not checking the level regularly you could run into trouble.

FWIW, my 2.5-16 had it's diff seals replaced on a major (£3/4k) M-B service some while back. Still looks slightly oily/grubby but it never leaks a drip of oil on the floor or anywhere and the level seems to be fine so I assume it's just an accumulation of dirt/oil film that wasn't cleaned thoroughly at the time?

If the level was low I'd be concerned though!

Will

Gotta agree with you here Will, am i right in thinking if MB stopped being conservative and started using more LSD's that this wouldn't happen as much?

Aren't LSD's are far more robust than open differentials? Or is that just me being silly?

 

[bluevenetian]

Apols for being mechanically ignorant...but how would one top up oil for the rear differential on a W124 estate?

 

[BlackC55]

There is a filler bung on the side. Fill until it drips out.

MB diffs always leak until the seals are replaced and that seems to cure them for a very long time.

 

[Will]

Apols for being mechanically ignorant...but how would one top up oil for the rear differential on a W124 estate?

With the car sitting level, undo the filler plug (there's two, it's the top one) and fill it with the correct oil until the oil level is as high as this filler plug opening.

It's a large allen/hex bolt (12/14mm?) so you'll need a decent bit and a decent bit of leverage.

Will

(doh - late posting! )