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Replacing MX-5 CV Joints: A Word of Caution
micksalt - 11/9/15 at 07:51 AM

If, like me, you damage the end of the outer CV joint trying to free it from the splines of the hub, chances are that you'll need a new CV joint. The good news is that they're pretty cheap (£32 a pair for me), and easy to remove (take off gaiter, hit with hammer from the back). The bad news is that there are two variants of driveshaft, ones with a 22-spline end, and others with a 30-spline end (credit to sdh2903 for this information). Remove your CV joint first and count your driveshaft splines before you order, or else you may well end up with the wrong one. It seems that the splines to the hub are all the same at 26 splines, so it's just the inner part of the outboard CV joint that you have to worry about.

Which brings me onto a question, where are people finding the 22 driveshaft-spline outer CV joints? I can find ones with ABS, but not without, but does that matter, will they both fit?

[Edited on 11/9/2015 by micksalt]


sdh2903 - 11/9/15 at 08:54 AM

Doesn't matter. As long as the splines are correct the abs side of things doesn't affect them.

Got mine from J and R driveshafts. 30 of quid for a pair with a 2 year warranty.


micksalt - 11/9/15 at 09:25 AM

quote:
Originally posted by sdh2903
Doesn't matter. As long as the splines are correct the abs side of things doesn't affect them.

Got mine from J and R driveshafts. 30 of quid for a pair with a 2 year warranty.


Thanks for that, do you know if you can knock the ABS reluctor rings off? I'm thinking weight saving, rotational mass reduction, unsprung weight reduction and removing a muck trap. Obviously it'll invalidate the warranty but the cost of the parts relative to effort it would take to remove the part wouldn't make the warranty that valuable anyway.


coozer - 11/9/15 at 09:27 AM

Thanks. Can you explain how the CV joint comes off the stub axle? Not just press fit is it?

My upright has been soaking in penetrating oil for about 4 months now and my next attempt is going to be welding up a jig to hold it and a 20 ton bottle jack to see if I can get to out.

It would be nice to remove the shaft to make this a bit easier, so far I've removed the gaiter, released the outer circlip but its still tight in there...

I may have to source a new upright without the shaft in it!


DW100 - 11/9/15 at 09:29 AM

Normally the abs rings are just a shrink/press fit and would knock off.

But it'll only be a few grammes


micksalt - 11/9/15 at 09:41 AM

Coozer,

The CV joint is held onto the driveshaft just by friction, and being that this area is soaked in grease, it shouldn't be seized. I cut off the tabs to the boot, peeled the boot back and then secured the driveshaft in a vice, I then hit the inner part of the CV joint, being careful not to contact the driveshaft and it came off with not too much effort. Since you have the weight of the hub and upright still attached to the end of your CV joint, I'd tie them all to something so when it does come off, it won't land on your toe.

As for getting the CV joint out of the hub and thus freeing your upright, it sounds like yours is as bad, if not worse than mine was, The solution was the biggest oxy-acetylene torch we could find to get the hub white-hot and thus greatly expanded, then just hammer on the end of the driveshaft whilst supporting the whole assembly in a heavy-duty jig:

BigJig
BigJig


Yes, the CV joint will need replacing after all this and the bearings, but as long as the hub is allowed to cool naturally (rather than being quenched), I'm reliably informed that it shouldn't harden too much. You do need the proper oxy gear though, the medium-sized torch couldn't rouch it, so I can safely say that any propane-powered lamp wouldn't have even tickled it.