weeping rear diff

[stuthemong]

Hi Guys,

A car I'm looking at has a weeping rear diff. It's tough to see where from, looks to be something to do with the back cover. I saw it was moist+1drip on the bottom, so cleaned up with a rag before a test drive. Upon returning a film of clear fluid had collected on the bottom edge near the rear cover again.

I know it's a bit 'how long is a peice of string', but is this a known fault? What could it be? Any one have any ideas of complexity at getting at it to repair, or would you leave as-is?

Cheers,

Stu

PS. The oil pressure on this car was around 80-90PSI cold, and something like 50 Odd hot. I was wondering if the 80-90 was a little on the high side, or is this fine?

PPS. How difficult is it to change a rack on a cerbera too - lots of hassle, or quite a easy DIY (+ a profession geo after, obviously)

Edited by stuthemong on Friday 26th June 12:10

[plumAJP]

weepy diff would be from broken down sealant between the back face and diff housing. (thats if its weeping from around the face joint)

mine weeped like this but would leave a 10p patch on the drive over a weeks standing.

i emptied the diff, wire brushed the diff and areas, cleaned with petrol to degrease, them smuthered the joint with gasket sealant.

i did not remove the diffs back plate, i did everything in situ, it is now clean as a whistle and no more drips. and no saturated areas.

steering rack seem ok to remove, i have not done it but from my refurb i could see the rack and how it was fixed, should be do-able if you can handle a spaner and socket set and fancy a little frsutration.

as for oil pressure, cold idle seems ok. im not sure on hot idle, mabe a little high. wait for someone else to confirm for hot idle

Edited by plumAJP on Friday 26th June 13:15

[FUBAR]

plumAJP said:

as for oil pressure, cold idle seems ok. im not sure on hot idle, mabe a little high. wait for someone else to confirm for hot idle

Id say it was the other way round. My cold idle is 60-65 and hot idle 45-50 (rising to 60ish when straightening the right leg )

[WIL35]

The oil on the diff could be coming from the breather on the top if it has recently been topped up.

If it is coming from the output seals or the input seal, they won't be that tricky to replace.

[stuthemong]

Thanks guys. I actually gave Joo a call too, and he has put my mind at rest over the rear diff - TADTS - the sealant idea is a nice one, I may try it as it doesn't sound too tough

The steering rack issue is not something I'd seen (despite reading this forum daily for months!) but does seem to a be a big weak point on the Cerbera. Drips/puddles under the car are a real pain - it's something I'll have to look into but a guaranteed cheap fix seems not to exist. Rebuilds not guaranteed, refurb'd racks liable to do the same I guess, and new racks at 1K... well, I Can see why that other rack thread about alternatives has just been put up. I guess I'd attempt to change the input seals in-situ, as I understand is possible, and cross my fingers. If that doesnt sort it, I could even try fabrication a little catch tank or something so a couple drips land in it, and are blown out on a run, which is preferable to it dripping on the drive. Obviously keeping a beedy eye on the level and topping up weekly if needed. It sounds like a bodge, but unless it got worse I can't see there being 1K part + labour worth there over a few drips. If it was £500 for a known fix I'd get it done, but it seems liable to just do the same.

Anyway, things are progressing well I think, provided an inspection goes well I may well be Cerbied in the near future. Woot.

Stu

[al 350i]

the rack is a bit of a pig to get out because you have to remove the water hoses and pipes but if you can do the labour yourself a rebuild from power steering services is only £130 + vat.

bit worried about oil pressures on mine now!!! as i get 45-50 psi when cold, when its upto temp i get 40 psi at 2000rpm but only 30 psi at idle and if really hot in traffic (90 degrees) will drop to 25psi.

is this bad?