Replacing De Dion diff output oil seals

[NigelJ]

Hi All

 

I had my 7 (99 SLR) MOT'd at the weekend (Passed *smile* ) and while it was in the air I had the opportunity to inspect the underside and grease the propshaft joints.

 

BUT there is a significant leak from the diff offside output seal so it needs replacing. All tips on this would be very much appreciated. I suspect there may be a bit of "technique" needed but can it be done ok with the diff in the car?

 

Cheers

 

NigelJ

[Paul Formston]

Hi NigelJ its not a bad job you need to remove the drive shafts by removeing the wheel bearing carriers, so its brake calipers off, discs off, and bearing carriers off then remove the shafts and fit new oil seals to the Diff and reassemble hope that helps Regards Paul

[Neil Williams]

Nigel,

 

You can cut down slightly on the dismantling work by removing the de dion ear, rather than the hub and bearing carrier. Doing the job this way avoids the need to disturb the hub, brake disc, bearings and housing. Just remove the brake calliper, pads and support bracket as previously described. Then undo the four bolts holding the ear to the tube. The whole shaft, ear and hub can then be removed as one unit. Replacement of the seal is straightforward; just make sure you tap the new seal in nice and square.

 

Regards,

Neil

[NigelJ]

Paul & Neil

 

Thanks for the info.

 

Cheers

 

NigelJ

[Andy A]

Thats the way -

Alternatively leave the brake calliper in place - make sure you undo your brake pipe and detach handbrake cable first.

Undo the 4 bolts and you slide out armfulls of hub and calliper and drive shaft...

 

 

 

Edited by - Andy A on 7 Jun 2006 12:34:07

[Paul Formston]

Hi Neil yes never thought of that, yes that will cut down the work Regards Paul

[simonbell]

Getting the old seal out can be a RPITA

 

Simon Bell - Caterham 7 Duratec R

I`ve seen the future.....and it`s powered by duratec Check out the website here

[Neil Williams]

Thanks Paul.

I worked out doing the job the way I described because at the time I did not have a socket large enough to undo the hub nut. I think there are several other threads in the archives that mention doing the job this way.

 

As an aside to Andy' A's post, some further work can be avoided by tying up the brake caliper with a ty-wrap (or something similar) this negates the need to disconnect the handbrake cable and the brake pipe. Bleeding the brakes afterwards can then also be avoided.

 

A this rate Nigel will be able to fix his car without doing anything at all!

 

Regards,

Neil

 

 

[NigelJ]

Thanks again for all the info. Can you guys tell me what actually holds the output shaft into the diff. It occurred to me that maybe the leaking one in not fully "home" so the seal would not be in correct contact with the sealing surface.

 

Cheers

 

NigelJ

[prs]

Nothing, it basically just slides onto the splines it can't come out as the other end is bolted to the hub.

Phil S7SVN

[NigelJ]

Phil

 

Yes I get that but the joints in the shaft allow plunge, i.e. variation in the overall driveshaft leangth as the suspension moves so if both ends are not fixed and there is friction in the joints then what stops the splines sliding in and out of the diff causing a leak?

 

Apparantly nothing, hence my question. On other cars I have seen a circlip arrangement fitted to the diff end of the shaft that clicks in to hold everything in place. Is this not the case on 7's?

 

Cheers

 

NigelJ

[DohNut]

 

Are you 100% it is the oil seal - I suspect it is not.

 

If it is sticky splatter over the petrol tank and boot floor (underside) and bulkhead then I suspect you would have a driveshaft boot split. When you are going fast the grease gets hot and runnyish and is flung outwards. Splits are often at the peak of the ridges and not very noticable.

 

There is no such mechanism for the diff oil, its static level is below the driveshaft seal and just gets splashed around pretty randomly in the diff during use.

Do you know what diff oil you have it is often coloured (red?)and does not tend to get blackened with use like engine oil.

 

However you may as well remove the drive shaft to get a new boot on.

 

Nick