Diff output shaft leak

[Heuer]

I seem to have developed a leak from the diff and it appears to be coming from the n/s output shaft seal. Anyone tried replacing the seal with the IRS in situ?

[tinworm]

Yes you can do it ok, The difficult bit is taking off the caliper to remove the disc - once you have unbolted it (carefully removing the shims) you can revolve it around the disc and drop it off the bottom. There is enough room to do it all if you are patient.

regards Barrie

[1954Etype]

David, if its the leather type, it may just have dried out?

[Heuer]

Rebuilt 12 months ago by the previous owner's representatives so don' t think it has dried out. Only started leaking in the last few weeks since driving the car in anger. Gearbox leak, petrol tank leak, engine oil leak, gearbox leak - I could go on. If you live in Shropshire/Cheshire I can give you a list of people not to use in your restoration! Fortunately brains beats shitforbrains so the old girl is rising like a Phoenix and is now 100% despite the "if a jobs not worth doing it certainly is not worth doing well" attitude of those involved.

[christopher storey]

David - please would you pm me with your non-recommendations ! Also , if you are prepared to disclose it, since it sounds as though the car came from my area, where did you get it from ?

[Heuer]

Christopher

Will PM you tomorrow. The car was 98% when I bought it but they did not go that last 2%. 123 OHY was winning concours events back in 1976 and continued to do so for the next 30 years. Full history from new and I am due to meet one of the early owners shortly. Maybe standards have changed but the car deserves to be as near perfect as possible. So with input from Angus Moss, Paul Brown, Richard Smith, Peter Crespin, Paul and Charles at Sherwood Restorations amongst others it is getting there. Actually I am thoroughly enjoying doing it - sort of icing on the cake stuff - and love the car but it highlights what it is easy to miss. I am becoming more knowledgeable on the early cars than I expected. Next, Cheney clips, report to follow.

On to the oil leak - do we reckon the lipped seal is the culprit or do I need to dig further towards the O ring?

[PeterCrespin]

Most likely the seal. However, if you can douse the area with carb or brake cleaner you should be able to blast it all dry as a bone. You can then leave the car and see where it weeps from perhaps while stationary. If it doesn't weep leave it overnight with the dry side raised to try and make sure the oil level comes above the suspect interface. I have left a leather re-sealed diff for weeks lying on one side after another, following seal replacement and fresh oil and not had a drop leak out. Not very practical with a fully assembled car though eh? If you knew from a receipt or whatever that they are plastic seals you could maybe try seal conditioning additive but you'd need to drain a bit of oil to make room and that dilutes your protection a fraction.

The above all assumes the breather is clear. Did the early cars have the same system? If it only began happening after you began caning the old girl, it could be a pressurization leak that disappears during more gentle use. Not that it's much of a solution!

[Heuer]

Thanks Pete. Someone else PM'd me suggesting the breather could be blocked and it was going to be my first job this morning because when I removed the filler cap yesterday to check the level there was a slight 'pop' suggesting pressurisation. I notice the breather has been over painted as well so it could be the culprit.

[Heuer]

I have learnt two things this morning - 1) POR15 is an excellent sealant and 2) give a grease monkey a paint brush and he will create a masterpiece:

[Heuer]

Having been running the car over the last few weeks I went under it and found oil coming out of the diff again but not from the seals. They were weeping slightly but not enough to cause the amount of loss I was seeing. I took the car up to the ever helpful Ken Verity and sought his opinion. He suggested the output shaft seals were probably to blame so he took out the IRS. It was apparent that the IRS had not been rebuilt with the same level of care as the rest of the car and the clown employed to restore it decided a thick coat of black paint and a random selection of the wrong bolts not tightened up should the order of the day. Ken is a perfectionist so decided to replace the seals which were marked 'Retainers 275-187-12' as the leather was hard and while he was at it he swapped out the APB Spain bearings for Timken ones - the old ones just fell out they were such a poor fit. He fitted a new filler plug as he reckons they can leak. With the diff back together it was filled with oil and left overnight. By the morning there was oil leaking out. Ken then changed the rear cover gasket but there was still leaking oil which was most perplexing. He checked all surfaces for cracks and then noticed one of the mounting holes was wet. With a bore-scope pushed in he found this:



That black dot at the bottom is a hole going right through the casting so oil was making its way under pressure up the thread. No idea how it got there and Ken had never seen anything like it before. He repaired it with epoxy filler and the diff is now leak proof. Big thank you to Ken for solving something that was driving me mad.