Spitfire Diff Rebuild

Started by MiniDave, July 04, 2018, 10:30:12 AM

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MiniDave

A friend brought in a Spitfire differential, my brief is to check it over and put new seals and gaskets.

On teardown the first thing I noticed is the gear oil looked and felt like  it has been in there since day one! I'm not sure what year diff this is, the car is a '66 but the early diffs prior to '70 had a split pin on the pinion nut, this one does not, nor does it have a hole for the split pin to go thru, so I'm waiting for the owner to call and let me know.

Edit: he just called, the diff is from a 74 - he's using it because it has a 3:89 ratio vs 4:25 in the original one

So tomorrow I'm off to Vicky Brits for the new seals and gaskets, then I'll put it back together and he'll be back on the road again.

A couple of pics of it torn down.....it sure is handy to have a bearing spreader and a 20 ton press!



Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

jeff10049

Differentials are kind of fun to go through having the right tools sure helps I always like setting them up as it's one of those things that's mysterious to most people.


MiniDave

Yes, there can be a lot of fiddling to get them just right. I'm only changing the seals on this one, not going to mess with the shims if I can help it.

Helps to lnow exactly which diff I have, tho only the front seal is different and I would have taken the old one with me to the parts place to make sure. The nut looks like it was loosened last time with a hammer and chisel so I'll try and get a new one of those too - over $10 for that stupid nut - some prices these days are completely bonkers. The seals are about $3 each.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

MiniDave

#3
Got the pieces I needed and put the diff back together today, it all went fairly smoothly and he'll come get it tomorrow.

The one fly in the ointment - the ring gear is showing some wear. I don't think it will matter as he probably doesn't drive that many miles, but I wonder whether it will be noisy. He's not going to buy a new gear as new ones are about $500 for the ring and pinion.

If you download the pic you can blow it up and see what I mean on the gear.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

jeff10049

I wouldn't worry about that gear it looks ok. If you end up re-setting it up I have had the best luck doing a contact pattern on the coast side of gears that have some wear.
looks like the pinion was set a little too far in on that. But I would leave it where it's at for fear of noise if moved as the wear has been established.

MiniDave

I decided the same thing, so that's what I did. It still might be a little noisy for all I know, but when you buy used parts you get what you get. At least now it won't leak.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

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