SKCC - Southern Kit Car Club. A Club for kit car owners across Southern England. Kent, Sussex, East Hants, Surrey, Berks, Middlesex, London

I had leaks on the output of my non bolt on (not a lobro) sierra diff, so when I was changing my rear brakes I replaced the seals. I think there's two sizes of seals so it depends on which diff you have. Was a pain to get them out but managed it with an assortment of seal pullers, screws, screw drivers, pliers and a bit of swearing. New seals went in OK and no leaks since

If you take the bearing housing / castle nuts out though doesn't that upset the backlash? So not really a job for DIY

I didn't need to touch the castle nuts, but that might be as mines a push in one...

Just had confirmation not to remove the castle nuts as it can upset the settings..

leegav wrote:It's been back twice Rob, and it's 10 hours driving to take it then ten hours driving to collect it plus fuel, accomodation for overnight stay and rental of a trailer. And if I wanted to send it back on a trailer without me driving it's 350 quid.

I figured it's easier to take local.

Can the diff leak through the bearing housing down the threads...

Surely it’s not your problem though lee, obviously I don’t know the why’s and why nots but I took it you bought basically a new car so any problems aren’t coming out your pocket ?

Talking from personal experience, sometimes you lose faith in a company to such an extent that you don't trust them to sort the problem anymore.

With Caterham, I was very reluctant to let them touch my car after it was registered. Whatever the rights and wrongs, I knew I would get any problem sorted properly and with much less aggro.

During the one year parts only warranty, a rear calliper leaked. The Caterham supplied ones are well known to be crap, so I sourced two used ones from Dick which are still serving well. Afterwards, I did get Caterham to send another to me so I have two spare now. But the money I paid Dick was well spent, I knew they'd be good and I got the car back on the road in days rather than
weeks.

I hope you can start enjoying your car soon Lee.

At Rob,

Agree mate...it's not my problem but I've lost faith in them now. They've stopped replying to me and I do not trust them to sort it out.

I've stripped the diff and shafts tonight, the shafts look in good condition. I then decided to slide a new seal over the shaft to see how it fits. Interestingly once over the spline lip the further up the shaft the seal goes the tighter it gets... Not masses but enough to notice. Once the seal is inside the castle nuts / bearing housing it will be slightly tighter too. So then decided to measure the depth of where the seal was sitting in relation to the shaft inside the diff. My conclusion is that the seal was way too far in the bearing housing to sit on the tight part of the shaft, thus causing a leak.

I can see marks on the shaft were the seals were before I had them replaced, and the recent ones were even further into the diff which is probably why they were leaking more so after replacement.

So I have measured exact depths the seals should sit inside the bearing housing relation to the shafts and I'm hoping this should cure my problem.

Picture 0346 shows how deep they were in the diff, and a couple of the others show where they should be.

First I have to put the back end together again

I think that mine were in the 'out' position but I'd have thought that they should butt up against an internal flange. Below is a picture I took as I was in the process of removing a seal, not sure if it's any use....

.

I guess when they were originally designed the shafts on the sierras may have been correct lengths to Start with so they would have butted up. My left drive shaft had more of a taper to it than the right side shaft after I slipped the seals over. So all shafts may be different. I guess if you bought an expensive couple of drive shafts then they may be on spec exactly?

But mine are not exactly the same...or the seals are not exactly the same..

If they still leak after this I am going to double up each side and use 2 seals.

And the company that put the two new seals in have admitted liability for not measuring and just knocking them all the way in. They have offered to change my master cylinders over to AP racing cylinders later this year for free if I supply parts. The ones I have are cheap non branded ones and based on the fact my brakes were not great and these originally were leaking too I’m not confident in them..