RichardS

Just to bring this thread up to date ...... the balanced propshaft with new UJ bearings plus the new output bearings and seals in the differential finally sorted out the vibration. I also changed the gearbox output seal whilst I had the prop shaft out so she's finally oil tight. Even with the balanced prop shaft, she still wasn't pulling well above 70mph so I've also had to replace the brake servo which was letting air in an weakening the mixture and replace some dodgy wiring (a 12V coil and 12V electronic ignition unit was fitted by a previous owner but the ballast cable was still being used) but I took her out for a test run yesterday and she reached a genuine 90mph without too much difficulty. I still need to get the mixture spot on but I reckon that she would have reached 100 if the traffic were lighter but once you get above 80 then it all feels a bit "sketchy" and definitely not relaxing. However 80 is comfortable cruising speed and means that I can keep pace with motorway traffic. Anyway, I'm feel ready for another trip to "Caffeine and Machine" but a bit faster this time. I wonder if I'll be invited to park her up on one the the show plinths again this time. 😉 Richard

Hi Jim I can't answer your specific query but my vibration was always there above 70-ish and never seemed to stop although I don't actually know yet whether the prop shaft is the culprit. I did have an intermittent metal grinding sound but that turned out to be one of the front wheel bearings which was so shot that it allowed the disk to deflect sufficiently to occasionally touch the shield and was instantly cured with new bearings. My prop shaft is currently at Dave Mac Propshafts in Coventry. The guy there said that the slight misalignment in the yokes would not have been the problem and showed me a new Land Rover propshaft with the yokes misaligned by 45 degrees as prescribed by Land Rover. However, he suspected that the sliding joint was somewhat worn and might the throwing the shaft out of balance and making it impossible to balance. They will either sort it out or suggest a new shaft which they can also supply so we'll see. Richard

Indeed. I didn't check the alignment before I split the prop shaft but whatever is it now, it must have been the same before. I'm going to take it for balancing to a prop shaft specialist so will ask them what they think about the misalignment. If they say that it is scrap then I'll accept that and chuck it away. The new bearings will have been a waste of £20 but replacing them was a good learning exercise so no harm done. Richard

I've now installed the UJ bearings at the diff end and managed to do that without user error. However, I cannot assemble the splined end symmetrical with the fixed/diff end. There is a minimum error of about 10 degrees. Is this a significant misalignment? Richard

The telescopic prop shafts that I've seen on other cars seem to have the sliding section at the gearbox end like the Triumph, although I've no idea whether it makes any difference.

I reckon that would put me off car maintenance for life! ☹ The most annoying thing with the UJ's, apart from user error issues, is that fact then the cap does not press out fully but you have to grip it to pull it out the final third. Why is it not designed so that the cap presses completely out of the sleeve? It would surely make the whole job much easier. Richard

You were spot on Pete. 😊 When I looked really closely at the assembly I could see that although the two caps were centred halfway across the circlip groove, the actual spider was fractionally off to one side so it was obvious which cap needed to come off. Anyway, off it came and one needle was sitting across the bottom of the cap. I was being so careful not to dislodge any of the needles but was obviously only 75% successful with my first UJ rebuild! Let's hope that I can hit the elusive 100% with the other end! The clips all pinged into place with a click and the joint is notch-free compared to the old one which seemed to have a preferred central position. Many thanks for steering me in the right direction and saving me a lot of time. Richard

That was what I thought might be the problem although I did not knowingly squeeze the yokes and they do appear to be aligned correctly. If there were no more likely explanations I was going to try forcing open them open a bit. However, I suspect that Pete has hit the nail on the head but we'll soon find out. Many thanks for the suggestion. Richard

I specifically tried to avoid this by making sure that the spider was able to move freely from one side to the other as I pressed in the second cap. However, your suggestion does fit the symptoms and the misalignment sounds about right so thank you for that suggestion. I will reassemble it again and post the result on here. Richard

I've been trying to sort out the vibration on my GT6 as per my previous thread which I ended with the decision that I was going to replace the UJ's and get the prop balanced. However, things have not gone to plan, as is sadly becoming the norm for me with this car. Anyway, all opinions as to what is going on are welcome. I bought two of the more expensive UJ's from Rimmers, the ones without the grease nipple, as the ones already fitted were without nipples and were full of grease when I dismantled them. I started the fitting the first UJ at the gearbox end of the prop shaft. I removed the short sliding section to make it easier to manipulate. I pressed the the first axis into the flanged section and that was fine. It centralised OK and the two circlips fitted fine and the joint was smooth and notch free. However, with the second axis into the prop shaft stub, it soon became clear that if I tried to press both bearing cups in far enough the fit the circlips, the bearings would be absolutely rigid. In fact, it is not even possible to press the last bearing cup in enough to get any of the circlip slot visible as the assembly is already totally rigid. I've played around with it a bit this afternoon and if I press both sides until there is about half the circlip slot visible on each side then the bearing rotates correctly. This is good in that at least the spider is central in all planes but, of course, it is useless as I can't install either of the circlips. Has anyone else experienced this issue? Many thanks Richard

Outer ball bearings and seals only. Richard

OK. Whilst the car is up on lift with the diff out, I've used a couple of high-level jacks under the rear drums to try and re-create the "diff grabbing" effect. Guess what ..... I now believe that it's all down to the GT6 rear suspension geometry which, when the wheel drops down freely to it's maximum travel, partially applies the handbrake as the linkage comes under tension. It seems to happen more obviously on the nearside wheel, perhaps due to it being further from the mechanism or perhaps the adjustment is slightly tighter on that side. This would certainly cause the offside wheel to scrabble on the gravel drive. I'll forget the diff being the source of the vibration but have already put new drive shaft ball bearings (I'm going to use 9 ball rather than 8 ball versions) and oil seals into my basket as I might as well refurb it. I've now removed the propshaft and it looks dead straight when checked with a straight edge although I appreciate that does not mean it's balanced. However, there are two welded on balance weights so it has been balanced. However, the UJ at the diff end is rather "sticky" in one axis and feels as if it wants to self-centralise. I've no idea whether this could set up such a bad vibration but I'll strip it down tomorrow. Richard

I've never heard of "Vibration Free" but they're not far away from me. I'll email them once I've got the diff refitted. Edit: Actually, whilst the diff is out I think I'll remove the prop shaft and have a good look at it. Thanks Richard

You could well be right about the prop shaft. Richard

There is a swishing sound as the drum rotates due to the shoes kissing the drum but certainly no binding in the normal sense. However, you have picked up on what I see now as an issue in that I was doing all the tests whilst sitting in the driving seat as I was on my own. I really needed a second person to actually see what was happening on the nearside. Unless someone has a better idea, I'm going to rebuild the diff with new ball bearings and oil seals and repeat the tests with a helper. If it's not the diff, and I'm now doubting that it is, I'll turn my attention to the prop shaft. Richard