Ali King Posted February 22 Report Share Posted February 22 Hi All, I finally got round to fitting new rear hubs - it had been on my to do list for a while, but I was finally spurred into action by the article in the latest TR Action. I got the new hubs from Moss and they appear to be reasonable quality items. However, I am now stuck trying to fit them to my existing universal joint on the drive shaft (pic below). The existing drive shaft and uj are reasonably new, so not replacing them. My problem is the old uj caps seem to be too tight a fit in the new uj yoke that came attached to the new hub. After getting one halfway in and then trying to start the other side it dawned on me that they were not going to fit and I was/am going to have trouble gettting them out again if I go any further (I was using a vice to squeeze them together). At this point I decided to measure them: Cap diameter: 27.00mm (1.062in); Old yoke internal diameter: 26.92mm (1.058in); New yoke internal diameter: 26.80mm (1.055in) (subject to my discrepancies in measuring - more difficulty measuring the internal diameters with my cheap caliper). So it looks like there was roughly 4 thou interference fit on the old yoke and 7 thou on the new one . Can anyone advise on whether this is too tight? Should I just go ahead and try and force it in with the danger of getting stuck halfway? Is that the kind of difference that I could remove with emery cloth on the inside of the yoke? Do I need to get it profeesionally reemed? Should I send them back to Moss? Thanks for your help. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted February 22 Report Share Posted February 22 (edited) What has the supplier said? Edited February 22 by BlueTR3A-5EKT Quote Link to post Share on other sites
Ali King Posted February 22 Author Report Share Posted February 22 7 minutes ago, BlueTR3A-5EKT said: What has the supplier said? I haven't spoken to Moss yet as I wasn't sure whether this kind of interference fit was normal, and I'm not massively confident in my measurements. However, I will give them a ring tomorrow. Quote Link to post Share on other sites
RogerH Posted February 22 Report Share Posted February 22 Hi Ali, I am surprised that you have a 0.004" interference fit - that is very tight and would normally require freezing of one of the components. They do not require an interference as they are held in place with circlips. Are there any burrs or other damage. Roger Quote Link to post Share on other sites
Ali King Posted February 22 Author Report Share Posted February 22 Just now, RogerH said: Hi Ali, I am surprised that you have a 0.004" interference fit - that is very tight and would normally require freezing of one of the components. They do not require an interference as they are held in place with circlips. Are there any burrs or other damage. Roger It could be that my measurement of .004 is erroneous - it seemed much easier measuring the outside diameter of the cap than the inside diameter of the yoke. I was the one who installed the uj in the old hub yoke some time ago and it went in with a fair amount of pressure in the vice, and also took a fair bit of coaxing to get out. However, even if my measurement isn't that good I'm pretty certain the new yoke is an even tighter fit, and probably too tight by the sounds of what you say. Quote Link to post Share on other sites
stillp Posted February 22 Report Share Posted February 22 59 minutes ago, RogerH said: They do not require an interference as they are held in place with circlips. Don't they need an interference fit to prevent them rotating? Pete Quote Link to post Share on other sites
RogerH Posted February 22 Report Share Posted February 22 Hi Pete, one of the JAG forums suggest that there is an interference fit - but 0.004" is having a larf'' There is a suggestion on their post that the rollers may be seized - that would grab the cap. I still feel that it should be a good sliding fit - not loose. I may pop along to my friendly propshaft shop and ask a question. Roger Quote Link to post Share on other sites
stillp Posted February 22 Report Share Posted February 22 Please let us know what they say Roger. Remember Ali is measuring with a caliper not an internal micrometer, so may well have measured the bore a little too small, it's easily done. Pete Quote Link to post Share on other sites
Nigel Triumph Posted February 22 Report Share Posted February 22 I wonder if the internal measurement with a caliper is accurate.... It can be difficult to measure internal diameters that way, external measurement with calipers is easier. I have fitted UJs to similar uprated hubs sourced from Classic Driving Development. The UJ cups could be squeezed in using the vice and socket method, exactly as expected, without excess resistance. Nigel Quote Link to post Share on other sites
RogerH Posted February 22 Report Share Posted February 22 14 minutes ago, Nigel Triumph said: I wonder if the internal measurement with a caliper is accurate.... It can be difficult to measure internal diameters that way, external measurement with calipers is easier. I have fitted UJs to similar uprated hubs sourced from Classic Driving Development. The UJ cups could be squeezed in using the vice and socket method, exactly as expected, without excess resistance. Nigel Hi Nigel, that would suggest a minimal interference or even no interference. Roger Quote Link to post Share on other sites
Nigel Triumph Posted February 22 Report Share Posted February 22 2 minutes ago, RogerH said: Hi Nigel, that would suggest a minimal interference or even no interference. Roger Yup, that's what I thought. The cups pressed in at ambient temperature, without the need for freezing the cups or heating the yokes. Nigel Quote Link to post Share on other sites
DRD Posted February 23 Report Share Posted February 23 I had a similar problem a couple of years ago when I fitted new driveshafts. Even using the correct tool I ruined one UJ and ended up taking them to a workshop to get done. I didn't measure it but it was certainly an interference fit. Darren Quote Link to post Share on other sites
RogerH Posted February 23 Report Share Posted February 23 (edited) Hi Folks, as promised I popped around to Propshaft Services in Feltham Middx. I asked the simple question - ''Is the cap an interference fit with the yoke'' and secondly do we know the tolerances of the both. Firstly I got - Yes. followed by a Possibly. Followed by on't know. Threy do know how to assemble there trhings but they simply do not need to know the sizes. I came home and dug out some used spares UJ and Yoke The UJ's are nominally 27mm (1.0629") I had 4 caps. I measured all four in two places at 90 degrees. Using a 1"-2" micrometer They were 1.063" (I couldn't do 1/10's thou) I had 1 yoke in very good condition. I measured both holes in 2 places at 90 degrees. Using a 6" vernier ca;lip[er (not didgtal) They also measured 1.063" (again, couldn't do 1/10's thou) I appreciate that the high end of one reading may be + 0.0009 and the other -0.0001 This could give apprx 1.8 thou difference . However I can see 0.5 thou on a Mic or Vernier gauge - so there is something maybe in reagion of a thou adrift somewhere. However (again) One of the cups could be push into position by hand.. Should the cap be allowed tp spin in the yoke - probably not. But what would make it spin. The needle rollers do not spin and the spigot on the yoke can't spin. However (again again) there is a slight rocking motion. So after a few million revs of the prop shaft the cap and bearing will not have done one full revolution at any time. They may do a composite revolution or two. Why would the cap spin - the needle rollers arw far free'er Back to the original problem. The yoke holes appear too small by 0.004". Assuming that it was measured correctly then it simply will not fit - it can't fit and then function. All the propshaft workshop do have the correct reamer - so if convenient take to your local workshop and get it reamed. Or contact Moss. Try fitting a cap without the needle rollers and see what the fit is like. Roger Edited February 23 by RogerH typo Quote Link to post Share on other sites
Ali King Posted February 23 Author Report Share Posted February 23 Roger and all, thanks for your replies - and Roger, that was going above and beyond the call of duty, much appreciated. I revisited the the problem this morning for about an hour. Due to the potential errors I decided that 'absolute' measurement were not crucial, but given that the caps had just come out of a pretty tight fitting yoke the key thing I needed to be interested in was the relative size of inner diameter of the new yoke comapared to the old. I did quite a few measurements of the old and new with my trusty cheap caliper assuming whatever errors I was making would average out as similar on both, thus measurements would be comparable. I ended up thinking the new one was 2 thou less than the old - better but probably still just too small. So I set about it with emery cloth and I think I shaved another thou off. But I still could hardly start the cap in the hole. Then I got my electric heat gun on the yoke and bingo I could just get the cap to start going in - just doing a trial insert at this stage. It soon jammed, presumably as the cap was reaching the same temp as the yoke. But easily got it out again. I then had to leave it, but when I get back I am now reasonably confident that I will manage to get it in with maybe a bit more heat and a bit of welly from the vice. I will let you know how I get on. Quote Link to post Share on other sites
RogerH Posted February 23 Report Share Posted February 23 Hi Ali, it certainly does come over as too small. You should be looking for an interference fit of possibly 1/2 thou. Any bigger and even your hot air gun will not work. Give it another go with the Wet&Dry. Even if you get it a fraction too big (loose fit) you could then use some 'Blue' LocTite Did you contact Moss - you really need to or raise a PQI form as others may get the same problem. https://trsdf.uk/projects#PQIIntroduction Good Luck Roger Quote Link to post Share on other sites
Tom Fremont Posted February 23 Report Share Posted February 23 I've never come across this, only too loose and have had some success peening the yoke holes back into tight[er] mode. One problem I've had is where a few thousandths of clearance between the cap and circlip caused a sort of rattling on low speed over-run. I now use only GKN or GMB kits; these are tight that way. Quote Link to post Share on other sites
stillp Posted February 23 Report Share Posted February 23 3 hours ago, RogerH said: Should the cap be allowed tp spin in the yoke - probably not. But what would make it spin. The needle rollers do not spin and the spigot on the yoke can't spin. However (again again) there is a slight rocking motion. So after a few million revs of the prop shaft the cap and bearing will not have done one full revolution at any time. They may do a composite revolution or two. Why would the cap spin - the needle rollers arw far free'er All good points of course Roger. I mentioned the possibility because one of mine seems to have been spinning - there are witness marks from the circlip on the cap, so one of them has been rotating against the other. I can't see any way the circlip can have rotated. It is on my list for further investigation, but the circular tuit hasn't yet been delivered. Pete Quote Link to post Share on other sites
RogerH Posted February 23 Report Share Posted February 23 Hi Pete, the problem is you can't tell how much it is spinning. Indeed you can see witness marks but possibly one complete turn may do that. Could the cap spin/move even if it had a minimal interference fit Fit and forget - then repair in 10 years time. Roger Quote Link to post Share on other sites
Ali King Posted February 23 Author Report Share Posted February 23 (edited) Update ... Job done - well one uj done, the other and re-assembly yet to complete. As I said my best estimate is that the yoke hole was 2 thou smaller than the old one which was already quite tight. At this I could not get one of the caps started in the hole, and I panicked a little when I got the other one half in but then it jammed. I set about the holes with some fine emery cloth and I think I increased the size by about 1 thou, though my measuring with a caliper must be a bit hit and miss. When I came to assemble it I ensured the yoke was warmed with my heat gun. I also lubricated the cap outer with the thinest oil I could find which was a household PTFE spray. I pressed it all together in the vice - it was quite tight, but all seemed well. I tapped it home with a hammer and socket to get it right for the circlips. Though not yet done, I'm assuming they same proceess will work for the other one. My thoughts on this: When I assembled the original uj in the old hub yoke I think it was a warm summers day, when I separated it and tried the new one, yesterday, the garage was pretty cold. I think I can take about a thou off a mild steel yoke internal diameter with about 20 mins of attack with a bit of finish emery cloth. I think about 100c (with a simple heat gun) increases the diameter of the yoke hole by about 1 thou. The use of very thin lubricant helps with the passage of cap into hole. Roger, Peter: As it fit in the end, and I'm not confident in my measurements or techniques, I don't think it's appropriate for me to lodge a complaint with Moss. Afterthought: I now have two old rear hubs. They look absolutely fine to my untrained eye. Presumably they could be checked and/or rebuilt by a competent supplier. On the basis that we should try not to throw any of our old parts away, what should I do with them? (Happy to give them to anyone to whom they have any value - collection only). Edited February 23 by Ali King Quote Link to post Share on other sites
RogerH Posted February 23 Report Share Posted February 23 Hi Ali, in all honesty I would pass the old hubs onto a scrap dealer. Imagine how you would feel if you gave them to somebody who then had a major accident because of them. Rest easy and bin them. Well done for getting them together. I would still do the PQI form - it may help others. Roger Quote Link to post Share on other sites
Ali King Posted February 23 Author Report Share Posted February 23 Thanks Roger, hubs will be on their way to the tip. How do I fill in a PQI form? Quote Link to post Share on other sites
RogerH Posted February 23 Report Share Posted February 23 Hi Ali, click on the link above and fill in the boxes. I think it is fairly straight forward. Give it a go. Roger Quote Link to post Share on other sites
Ali King Posted February 23 Author Report Share Posted February 23 24 minutes ago, RogerH said: Hi Ali, click on the link above and fill in the boxes. I think it is fairly straight forward. Give it a go. Roger Done Quote Link to post Share on other sites
keith1948 Posted February 23 Report Share Posted February 23 One big problem that can occur when re-assembling these yolks is one or more of the needle rollers falling over as you push the central part into the cap. It is then impossible to push them completely home and you have to take them apart again. You need decent circlip pliers as well. I use a smear of WD40 on the caps and push them home using a bench vice but a suitable sized G clamp can also work. Make sure there are no burrs on the yolk. They should slide together reasonably easy but not so loose that they spin. It is one of those jobs that should be straightforward and often isn't. I never reuse UJ's after taking them apart because I usually end up damaging them. Keith Quote Link to post Share on other sites
Andy Moltu Posted February 24 Report Share Posted February 24 I have come across U/Js that were so tight they could not fit. Other than cleaning of burrs on the yolk, I wouldn’t remove metal from here. It might be tricky to take much off the cups because they are very hard. They should, once they are straight slide in fairly easily using a vice. They should not be so loose they can rotate in the yolk. Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.