16 replies to this topic

[Jammy]

Ok, went to rebuild my diff tonight, didn't go as planned, couldn't get the blooming thing apart, got upto have the splined shaft that runs all the way through the diff, with the final drive still on as well as the cage, and one of the bearing things still on. Just didn't know what to do from there, could anyone give me a rough guide?

Also the output shafts from that diff have the standard universal joint on them. I've bought some 4 pot alloy brakes with driveshafts, and the driveshafts aren't the standard universal joint, there are just a hollow shaft, with the splines on the inside, no way of putting the castle nut that goes on the universal joint on. Am I still able to use the driveshafts that I got with the brakes, or do I need new output shaft? Which I'm guessing would require a diff rebuild?!

[Dan]

Don't understand what you mean. It would be much easier if you use the right names for parts. Do you really have universal joints at the inboard end or do you have pot joints? What splined shaft runs all the way through the diff? And there's no way you have UJ's at the outboard end. What brake setup have you brought?

I assume you've got just a diff with shafts sticking out of it and nothing else at the moment. You neeed to pull the bearings off the shafts first (you need a puller for this).

[Jammy]

Sorry, still learning what the names for are for everything!

Attached a few photos to better explain my problem.

This is the shaft coming out the differential (the output shaft?!)



This is the joint that came off that shaft (I called it a UJ, is it the Hardy Spicer joint?)



This is the driveshaft that came my my MiniSport 4 pot brakes (bought second hand, is this a pot joint?)

[Jammy]

So is it possible to use the driveshaft that came with my disk brakes (bottom pic) with the shafts that come out my diff at the mo?!

I've put them on and then fit and everything, put I can't see a way of fitting the nut that was on there before, will this matter?

[Dan]

You need new diff pinions. The output shaft you have is for the crappy rubber coupling type inner joints. You MUST NOT try to fit the pot joints to this, or their driveshafts. The best thing for you to do is to change the diff pinions for pot joint types as the rubber coupling type (or even the QH upgrades fitted to yours) is a bit poo and you really will be better off with the pot joints.

[Jammy]

Ok, well after a bit of a weird conversation with a local spares centre (was told to change from rubber couplings to pot joints wasn't possible as the whole differential and gearbox are different!), and then looking at the price of a new pinoin on MiniSpares (£150), I was a little disheartened!

However! The local spares centre did say that I got use the output shafts from an automatic! Woohoo, would do I have coming out of the Clubby?! An automatic! Well I've been and checked and it does have pot joint driveshafts! But before I change them over, I want to make sure this is ok?! I use the diff pinoins from the auto gearbox? Does that mean I have to use the FD from the auto as well, since when I was looking on MiniSpares and there was different pinoins for different size FDs?!

Also, is an 850 engine with a rod change gearbox and rubber couplings rare?

[bluebottle]

i think with a bit of fiddling you may be ok.....the auto ones if they arent pot joint ones will be the hardy spicer type, but unlike the cooper 's' the ends just slide on, and dont bolt on like your old ones.
so you could just swap the whole auto diff over, or just rob the outputs.



this picture is of the end that goes into the diff, auto ones of these aren't bolted on, and can be swapped for pot joints.

[Jammy]

And I should be ok taking that diff and using it on a manual gearbox?

[bluebottle]

as far as i know the diff will be the same, you'll just have to find out what ratio the automatic one is, and see if its suitable for your car.

dont forget if you change the diff itself, you'll need the matching pinion from the gearbox as well (thats the matching little cog)

[Guess-Works.com]

Crown wheels and pinions are matiching pairs, dont try and mix ratios otherwise you'll be chewing cogs,

Most autos have a 2.7 ( or there abouts ) diff ratio, so you're going to have to split the diffs. and make one good one out of both... Unless you want to stick with the magic wand box, I'd be tempted to just find a complete pot jointed rod change and be done with it....

[Jammy]

Erm, one gearbox is an auto, the other is a rod change?!

I'm just going to use the complete diff from the auto and use it on the manual gearbox since that diff already has pot joint driveshafts! Just one more question, the auto diff has a one piece diff housing, whereas the one on the manual gearbox has a 3 piece housing, which housing should I use? Or are they not interchangable?

[Guess-Works.com]

The diff housing, again ar a matching pair, so use the diff from the manual with the manual... you may come across issues with the cover plates, as those used on hardy spicer joints are slightly different than pot joints, but if you say the box from which they came from is a rod change ( not remote, nor magic wand ) then you should be ok with them..

[Jammy]

Ok, well then now I'm buggered slightly.

I have one manual gearbox from an 850, rubber couplings, and a 3 peice diff housing.

I have one auto gearbox from a 998, pot joints, one peice diff housing.

I need one manual gearbox, with pot joints. It can't be done using the two, can it?

[Dan]

Which gearbox do you have with the 850? It sounds like it will be a three synchro box to me.


I think you probably need a new box, but since you have two exchange core gearboxes it won't cost you all that much. Get in touch with a gearbox supplier and ask how much exchange you can get for those two. Or talk to Guessworks.

[Jammy]

The gearbox from the 850 is defintely a 4 speed synchro.

I know of a spares place not too far from me, a second hand gearbox that is working with diff with cost me £80. So I may go with this, and rebuild the 850 box for practice.

One more question (not sure when these questions are gonna end!!), will the one peice diff housing not fit the manual box (has a 3 peice housing on at the moment)?!