Thursday, 28 February 2013

Dodgy Flange Piece Oooh Errrh

I got the halfshaft assembly all built up with the brake shoe assembly and drum last night. Gave the assembly a spin to ensure the brakes weren’t binding and noticed there was a severe amount of lateral run out on the drum face where the road wheel would sit.

I checked it with my DTI gauge and the run out measured in at well over 2mm at a radius of 55mm. I calculated that it would have equated to a 12mm run out at the wheel rim, obviously not acceptable!

Measuring the Lateral Run Out with a Dail Gauge

I suspected that the most likely thing wrong would be a bent outer halfshaft although it could also be a bent hub. To be honest it was getting late and I was frustrated and I thought damn it lets just get a complete 2nd hand halfshaft assembly to bolt back in the car. Sent off various emails and a post on the Club Triumph forum after midnight last night to see if anyone had any for sale. Lots of responses from the Forum and one from a Wins International who were listing 2nd Hand halfshaft assemblies on their web site. Plenty of responses but having thought about it I have a new bearing, a new rotoflex coupling a vertical link with good lower wishbone bushes and a long bolt that’s not seized so it would be daft to go over to a complete unknown quantity assembly when most of mine is good. I therefore decided to strip out the hub and outer halfshaft and inspect carefully to find which parts are damaged.

The most obvious culprit, the halfshaft actually seems to be true, but the hub certainly isn’t. I put the back face of the hub the a flat surface block of my Vice and measured the distance to the front of the hub flange around the circumference with my digital callipers. Sure enough the hub is distorted, the largest and smallest flange distance dimensions differ by 2.6mm around the circumference!

Measuring the Hub Flange Distortion with digital Calipers

New hub required then. Post put on the Club Triumph Forum to see if anyone has any good 2nd hand rotoflex hubs, I’ll probably ravel up to the Triumph Spares Show at Stoneleigh on Sunday to either pick one up from a member or try and find one. Failing that Canley Classics do have new ones but they are about 80 quid, ouch!

The other pain is that I’ve fitted my new outer wheel bearing and extended wheel studs to the bent hub so I’ll have to carefully try and recover these.

Wednesday, 27 February 2013

Good Job I had a stock of spare outer halfshafts!

The work to replace the wheel bearing and rebuild the halfshaft continued tonight. I had a bit of advice from two well respected Triumph aficionados who suggested that it was better to have a bit of pre-load on the bearing and to leave well alone now I had come up with zero end float. However, the fact that the larger distance piece and 5 thou spacer arrived in the post today I thought I’d give setting up another go. Probably just as well as I ended up adding another 6 thou of adjustment to get 1 thou of end float measured and verified with my DTI gauge. I would have had 5 thou of preload if I’d left the setting alone which I think would have been too much so I’m happy with the end float now.

Bearings were then greased, oil seal added and everything assembled with the replacement half shaft I’d selected from my “good” 2nd hand spares. Except it turned out not to be a good half shaft after all, despite the fact that I drifted the assembly fully together first to save too much drawing the bearing down with the shaft and the thread on the shaft looked good it stripped before I got to the required tightening torque.
Damn It!

I then had to strip out the shaft, remove the big block spacer, dust cover disc and rotoflex coupling and build up another shaft. I picked what I considered to be the next best shaft, it looked good except there was a slight taper on the last few threads which is why I had demoted it to 2nd place. However on reassembly I torqued down the halfshaft nut to the top end of the 90-120 lb/ft setting, I used loctite thread lock, even more essential with the tapering of the end of the treads making the nyloc of the nut pretty much useless on the thicker than standard nuts that seem to be the only ones you can get hold of nowadays.

Essential addition, Loctite Threadlock due to the thicker than original halfshaft nuts now supplied by Triumph Specialists.

Torque wrench is essential to ensure the right Torque as it's bloody tight, 90 - 120 ft/lb

I was hoping to get everything ready for refitting the halfshaft to the car tomorrow night but the replacement of the stripped halfshaft lost me quite a bit of time. I’ll reassemble the inner halfshaft to the rotoflex tomorrow, build up the brake shoe assembly and replace the hub tomorrow night and start refitting the halfshaft on Thursday night. Hopefully everything will be fully back together overt the weekend and I can re-submit it for MOT next week. Unfortunately this will be past the 10 working day re-test limit and with the new computerised MOT system it will have to be a full test rather than a re-test. The MOT will also have run out by then so no legal way to road test the car until I’m on my way to the test station although I’ll no doubt run it around the block carefully before then.

Sunday, 24 February 2013

Slow Progress when you have to wait for parts through the post

Carrying on with the halfshaft rebuild but it’s a slow job when you have to wait for parts to arrive via mail order. Especially when you can’t order them all in one go. With the rear wheel bearing adjusted by a distance spacer and shims it’s not possible to work out if you need different spacer and shim combination until you get the unit assembled with the new bearing.

Anyway, I have got to the stage now where I’ve been able to determine that I need to order a different size spacer and shim combination. I drifted the new bearing races into place in the vertical link and assembled with the hub and bearing in a dry condition (ie no grease) to measure up. Using the one spare distance spacer I had plus two 3 thou shims I used the Canley Classics method of measuring using a straight edge across the bearing/inner shaft face using feeler gauges. It seemed that I would have an end float of 2 thou which is within the ½ thou to 2 ½ thou tolerance recommended by Triumph.

New Bearing Races Drifted into Place in the Vertical Link

Measuring the predicted end float using the Canly Classics Straight edge and Feeler Gauge Method

I then assembled with an outer halfshaft to check the end float with a DTI gauge. I used an old outer halfshaft and nut as the thread is a weak point and I didn’t want to risk damaging the replacement halfshaft with the unnecessary assembling and de-assembling. I drifted the assembly together to get a good portion of thread showing and then tightened up the axle nut to 110 ft lb which is towards the top end of the torque setting which draws the hub assembly onto the halfshaft fully home. Although the bearing was rotating freely I couldn’t detect any end float which was also borne out by the DTI gauge. I therefore reckon the distance spacer and shim assembly I have used is set with pretty much zero end float.

Checking the Bearing End Float with a DTI Gauge

I’ve currently used a 144 thou spacer and two 3 thou shims. I’ve ordered the next spacer size up, 148 thou and a 5 thou shim from Canleys. Although the 5 thou shim isn’t shown as part of the hub assembly in the parts manual it is available as a pinion shim part of the diff assembly. With the two spacers and 3 shims I should be able to come up with various combinations in 1 thou increments until I get the correct end float which will be verified with my DTI gauge. I’ll then assemble together with the replacement halfshaft and a new nyloc nut. 1 pain is that it seems non of the traders supply the correct nut any more, the original nyloc was a thinner than standard 5/8 UNF nut, but the last two suppliers I’ve used when doing halfshaft rebuilds have only been able to supply a full thickness nut which means there is very little shaft for the nylon locking to engage with. I’ll therefore use loctite threadlock on the assembly just to make sure.

Another job I’m doing at the same time is replacing the weel studs with extended versions and fitting 10mm wheel spacers to get around a clearance problem with the Cosmic Alloys potentially fouling on the shroud of the lower wishbone bush. I ordered a par of spacers on ebay that were supposed to fit wheel PCDs of 95 – 114mm. Triumphs have a 95mm PCD so these should have fitted. However although they go over the studs they won’t sit flush and fouled on the lower portion of the stud. I’ve measured the wheel spacers carefully and it seems they have actually been made with slots to suit a 100mm minimum PCD rather than 95mm. Despite the bubble packing stating 95mm! So trying to get a refund through ebay at the moment. I’ve already fitted two of the extended wheel studs so as a temporary measure I’ll use 2 6mm wheel spacers I’ve got lying around on the rebuilt shaft and leave the other side as is. The difference of 12mm on the offsets of each side shouldn’t make that much difference as a temporary measure until I can get a sensible set of 10mm spacers that fit.

Extended Wheel Stud Fitted

10mm Wheel Spacer

Spacer Won't Fit Flush

Tuesday, 19 February 2013

Half shaft rebuild underway

Still waiting for my rear wheel bearing to be delivered, card through the door from the postman while I was at work so I'll pick it up from the sorting office tomorrow. In the meantime I set about getting stuff ready to rebuild the halfshaft assembly.

I've decided to replace the outer driveshaft as well just in case there is something wrong with it which was causing the bearing issue. I had a choice of 3 2nd hand spares so I chose the best one, in particular the one with the best thread at the end which is a weak point. I've got a die nut the right size for the thread so I also ran that down the tread to clean it up nicely.

Replacing the outer halfshaft means the rotoflex coupling has to be removed, the coupling fitted is still in very good condition, however I had one brand new genuine metalastic rotoflex coupling in my stash of spares so I decided to rebuild the halfshaft using this. I now have two 2nd hand but good condition genuine metalastic rotoflex couplings in my spares stock. Although it would be a bit of hassle to refit these if I need a replacement as they don't have the temporary steel compression band in place that new ones do it would probably still be better to do that than fit pattern ones which wear out in 5 minutes and new genuine ones are now well expensive so I'll keep and cherish the used spares!

I've also ordered some extended wheel studs and 10mm wheel spacers which should resolve the issue I have with limited clearance between the cosmic alloys and the lower wishbone bush shrounds. Easiest to fit these while I've got the hub off although I'll change the studs on the other side hub in situ which probably means stripping out the brake shoes etc but no big deal.

So tomorrow once I get the bearing I can measure up and find out which distance piece I need to buy to set the bearing end float in order to be able to finish the job.

Shaft rebuilt with replacement outer shaft and new metalastic rotoflex xcoupling. The UJ was replaced 1000 miles ago so I've left that well alone. (Must get around to tidying up my messy workbench sometime!)

Monday, 18 February 2013

The horrors within!!

Got the drive shaft out of my car and stripped down the hub, shaft and vertical link assembly. Not a pretty sight....

The bearing itself actually looked reasonable, but it was pretty obvious why the play had developed. The inside face of the hub bears up against the adjustment shims which in turn face up to a distance piece. What I found is that the inside face of the hub had worn, the 2 shims that I had fitted had worn away to almost nothing (just a small portion of 1 remained!) and the distance piece had also worn on both the face and the outer diameter. Quite a mess.

All 3 parts are scrap. Fortunately I have a spare hub in good condition, just as well as they are over 80 quid each. I have a couple of shims and a new bearing on order. I'll have to build up the assembly with the new hub and a new bearing to see what size distance piece I require and if I need any more shims as the distance piece and shims take up the tolerances in the hub and bearing manufacture. I do have one spare distance piece but I'd be very lucky if it works out to be the right size.

And all this wear took place within 1200 miles and between MOTs! Nasty.

Chewed up inner face of the hub...All nasty and burred up, hence it's picked up some thread off my rag.

Worn Distance piece, this part should actually have a straight edge outside instead of tapers!

All that was left of 2 shims.

Sunday, 17 February 2013

Another MOT another wheel bearing!

Took the GT6 down to Moonface to get a quote on some bodywork the other day. The intention was to split the quote down into anything needed for the MOT and then the rest of the work as the MOT is up at the end of the month.

Jim down at Moonface suggestted best way to do this was to actually put it in for the test, I knew I had an issue with the rear nearside wheel bearing but thought what the heck, at least it will tell me anything else that needs doing.

Sure enough the wheel bearing failed the test, but that was it, no other problems. So I know what I need to do in the evenings next week, rotoflex wheel bearing change.

As any Triumph experts know chnaginmg a wheel bearing on a Rotoflex car is a PITA. To make matters worse, my car has been eating rear nearside wheel bearings for a while, the last one only lasted 1,000 miles and the one before that only 3,000 so something is definitly not quire right. The rear nearside is the axle that got knocked about a bit when we spun off the road after a near miss with a deer on the RBRR back in 2010 resulting in a broken tie rod so it could be that the outer halfshaft is slightly damaged although I couldn't find any damage when I checked it. It could also be some wear in the splines on either the outer halfshaft or hub so I've sourced some decent 2nd hand replacements and I'll rebuild the halfshaft with a hub and shaft change at the same time as the wheel bearing. I guess the other possibility is that the wheel bearings available now are of dodgy quality, like lots of our spares which seem to be sub standard far east manufacture nowadays, just hope this is not the case....

The bearing is adjusted using shims and a distance piece that comes in various sizes.  If I'm changing the hub then sods law the existing distance piece won't be the right one for the new hub. These were pretty much unavailable parts last time I looked but I can see that both Canley Classics and Mick Dolphin list some of the sizes now, in fact the same parts are avbailable under different part numbers for the 1300/1500 fwd models so fingers crossed the one I need will be available other wise I'll need to have one made up....