Oil Leak and "Nearest Equivalent" syndrome

[dasadrew]

I've been chasing an annoying small but accumulating oil drip from the rear of the gearbox since months. I'd finally narrowed it down to the speedo drive area, replaced the copper washer, tightened all up but to no avail. My speedo angle drive was a bit wobble, so bought a new one. Still a drip of oil. I'd already renewed the oil seal NKC105 - also to no avail. Renewed the "O" Ring NKC106; nada.

I've now disassembled the lot again, as the oil is definitely escaping from that speedo take-off. Had a quick flash of brilliance an noticed that the "O" Ring NKC 106 was only very slightly larger than the diameter of the housing NKC42.

I'd got a second set of "O" Ring and Oil seal from the first attempt. (I sometimes order inexpensive bits from two suppliers as deleivery times can vary quite a lot). Just compared the currently fitted "O" ring with a new one........

Current "O" Ring outer diameter is bang on 25mm
New "O" Ring outer diameter is 1" (25,4mm)

Can't trace back which "O" Ring came from which Supplier, but I'd guess one of them is using a "nearest equivalent" metric size.

I'm hoping I've finally got my leak licked!

Drew

Speedo Drive.JPG

[brian0443]

Have you been using metric oil again?

[mole42]

Hi Drew, I really think we should create a new technical section to highlight these imperial/ metric oddities.

My contribution is that there are some track rod ends which have the correct imperial thread for the rack, but have metric threads for the nut which fastens the steering arm. They are otherwise perfectly okay for the Stag.

Richard

[dasadrew]

Have you been using metric oil again?

Yeah! Gallons of it!

[mole42]

Yeah! Gallons of it!

[NickA]

I know this is quite an old post but I'm tring to work out how the hell the oil seal NKC105 fits into the housing NKC42 mentioned by Drew. The oil seal was very brittle and broke up when I prised it out. The new seal is very hard and I've tried pressing it in with a suitable socket but it just doesn't want to go. Does/should the seal press over the ridge that's visable in the end of the housing? Any thoughts/suggestions please?



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[Klaus Schlueter]

Drew, have a look at the website Diet und Rabenstein. That is my source for o rings as they offer many inner dia and thickness for each ring Klaus

[RobinLegin]

Drew, I thought all Stags like to leave their mark wherever they park up. At least that was what someone told me when I was wanting to cure oil leaks from the D cups. Now the old leak is somewhere near the transfer housing.
Es ist sicherlich normal

[davidf]

Stags don't have oil leaks - they have a reliable under-body anti-corrosion system.

[dasadrew]

Drew, I thought all Stags like to leave their mark wherever they park up. At least that was what someone told me when I was wanting to cure oil leaks from the D cups. Now the old leak is somewhere near the transfer housing.
Es ist sicherlich normal

Oil leaks from 'D' cups? ooer missus