Jump to content

New stub axle


Nevros
 Share

Recommended Posts

I recently had to replace a front stub axle on my Spitfire 1500 and ordered a new one from Rimmer Bros. Upon assembling it all seemed to go on fine until the caliper, which wouldn't mount with the disc central in the slot - the hub-side of the disc was running against the inside of the caliper. I hadn't changed anything apart from the stub axle and on closer inspection the gap between the hub and the upright was somewhat larger than it was both when I took it apart and on the other side of the car. Also, the castle nut at this point when done up to the correct spec was oddly too far down the thread to have the split pin through it. I had a suspicion at this point that would turn out to be correct on disassembly. The new stub axle is longer and has an ever so slightly different profile to the original. So much so that it just caused the hub to sit further out and throw all the alignment off kilter. Has anyone else encountered this, have any suggestions or know of any stub axle out there that is the correct profile and length?

20201213_171615.jpg

Link to comment
Share on other sites

There look to be very slight differences in your two stub axles, but not enough in the important bits to make a dramatic difference to the fitting. Are you sure it's fully seated in the upright? It's strange that the hub appears to sit too far out, yet the nut is too far in... have you tried it without the felt hub seal? See how it fits with that removed - as per the manual - then retighten to the same place with the felt seal refitted. Did you replace the bearings at the same time? 

Link to comment
Share on other sites

Hi Colin, I'm fairly sure everything's as far on and in as it will go, gave it all a good tap. Even so, the axle doesn't fit through the carrier as far as the old one. I share your sentiment about the nut position being odd, I haven't tried without the seal, I will do on my next attack, but I doubt it will make a difference as it wasn't being compressed in the first place as the hub wouldn't get close enough. I didn't replace the bearings as they're timken and in good condition.

Just thinking 'out loud' as it were, even if I got the axle to sit further in the carrier and solve the hub spacing problem, that would still leave the nut too far in. It seems the whole assembly needs to sit further in but the hub needs to sit further out on the stub. I am somewhat baffled and would love to be convinced I'm missing something obvious. 

Link to comment
Share on other sites

I nipped out to the garage to check on spares I have, although I suspect they're Herald rather than Spitfire 1500 - I had both but the new ones have gone, which now makes me wonder if I rebuilt the early Herald uprights with Spitfire axles. Will have to go check... again.

In any case when I trial-tightened the castellated nut over a D-washer, it went right to the end of the threads leaving one split-pin hole half out of the threads and the other almost completely. I'd still be able to bend the end of the split pin down to secure the nut if that happened on the car. I'm surprised that if Nevros' hub is being held away from the upright, too far out, then the other side is so far inwards that the split pin can't be used. Have a look at the depth of the castellated nut on mine; I know you can get thinner versions, which would wind too far in when fully tight.

DSCF0371.jpg.6cb159b1990c6a4008ee2c44f0fa11d8.jpg DSCF0370.jpg.16319fd677d334fa5405893dcaa26a23.jpg DSCF0372.jpg.6b38687312ab24e450bbc916c225f9a6.jpg

 

Link to comment
Share on other sites

3 hours ago, Colin Lindsay said:

I'm surprised that if Nevros' hub is being held away from the upright, too far out, then the other side is so far inwards that the split pin can't be used

I think, if the stub axle isn't fully home in the vertical link, then the outer bearing can slide far enough to let the castellated nut bottom out but not far enough for the inner bearing to go all the way home. It does need the stub axle to be quite a way short of fully seated, though.

Link to comment
Share on other sites

I don't like the idea that you have to polish the stubs or otherwise heat / expand the bearings to make them fit on the new stubs, as that other forum suggests. I've never yet had a hub that didn't seat first time bar one where I replaced the stub axle on a Herald, but not fully, and had to redo it. The TR7 I had demolished the bearings when I went to fit them, as per manual guidelines - fit first with no felt seal, torque up and mark where the nut goes to, then refit with the felt seal fitted and tighten to the same spot before inserting the split pin. When I went to pull the hub off again the bearing came apart and had to be very carefully forced off the stub axle. It's difficult to get an accurate fit / torque with the bearings so tight on the axle, and if you overtighten, how do you release again? Something isn't machined to the correct spec.

It seems on first read that Rimmers are just replacing customer's returns rather than addressing the cause; possibly they're not aware of the frequency of the problem?

Link to comment
Share on other sites

Afternoon gents, thanks for your patience and help. Been attacking other bits of the car and the other side where I don't need to replace the axle to see if it offers any insight. The offending hub and upright is sat on the table at home and after a very light rub with some 400grit the hub seems now to be going on further. I'll have to wait until I get it back to the car to see if the disc and caliper line up now. I definitely ordered UKC697, and received a stub in a bag labelled the same. 

I now seemingly have a similar problem to the chap in the link Nick posted although slightly different in that his bearing is going too far over the axle, and mine seemingly isn't far enough. The castle nut is tight keeping the outer bearing as far in as it will go on the axle and I have a good 1/4" lateral movement before the bearing sits in the track. I'm going to give this end a light rub of 400 grit as well to see if that makes any difference and I think I'm then just going to make the castle nut sit at the right height with a washer or two and then just cross the ill fitting grease cap bridge when I come to it.

Link to comment
Share on other sites

Well, good news and bad news. I put the hub on with the old stub axle from the other side to try and get at least one side finished. All went on well and as smoothly as one can expect, castle nut did up nicely. But. Caliper still didn't go on centrally. My only thought now is to get rid of a couple of mm on the inside of the caliper mounting brackets. 

20201218_110752.thumb.jpg.7bf26d495de32638d18643c8f143da09.jpg

But here's the comparison between the outer bearing positions on the old and new stubs, so I fear I may still have issues on the other side. 

20201216_161124.thumb.jpg.149668df551ca83f085565d46307575d.jpg

 

Link to comment
Share on other sites

Ah. Fairly sure. Cup facing the upright as I understand. I will have another look and make sure it's properly home as well. 

I wasn't really thinking when I took the first out, was on such a roll with dismantling. Have since realised I didn't really need to just to give the upright a clean up and a lick of paint. But I did and made the mistake of getting annoyed and used a hammer and subsequently bent the end. 

Found another few people who have had issues with Rimmer stub axles. Good to know I'm not completely mental.

https://www.triumphexp.com/forum/spitfire-and-gt6-forum.8/front-stub-axle-assembly.1705213/

Think I may do the same and order one from Canley.

Link to comment
Share on other sites

19 hours ago, Nevros said:

Ah. Fairly sure. Cup facing the upright as I understand. I will have another look and make sure it's properly home as well. 

I wasn't really thinking when I took the first out, was on such a roll with dismantling. Have since realised I didn't really need to just to give the upright a clean up and a lick of paint. But I did and made the mistake of getting annoyed and used a hammer and subsequently bent the end. 

Found another few people who have had issues with Rimmer stub axles. Good to know I'm not completely mental.

https://www.triumphexp.com/forum/spitfire-and-gt6-forum.8/front-stub-axle-assembly.1705213/

Think I may do the same and order one from Canley.

If you complain to Rimmers they will say they have never had a query over that part before - no matter what the part is.

 

Roger

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...