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

I've had a bad vibration from my GT6 above 70mph ever since I bought it. There is slight vibration well below that but it gets bad at higher speeds. My thinking was that it was something from the front end so I have had all the wheels balanced twice, replaced the front wheel bearings, steering column bushes, track rod ends etc. There is now no play anywhere at the front end and everything turns/spins smoothly. None of this work has made any difference to the vibration! I then decided to check the rear driveline so I jacked up the rear end of the chassis with two jacks and ran the engine in gear and everything seemed fine. I then dropped the nearside wheel to the ground and repeated the exercise. The offside wheel span freely as expected. I then raised the nearside wheel and dropped the offside wheel onto the gravel. At idle everything seemed fine but when I increased the revs a little the offside wheel started jerking violently as it tried to spin itself in the gravel. I repeated this exercise several times with the same result. I believe that if I had opened the throttle further, the offside wheel would have driven the car off the jack. The diff does not have undue backlash when the wheels and prop shaft are spun by hand and I now have the diff on the bench with the drive shafts out and it all appears to be in reasonable condition with just a little scoring on the sun/planet wheel teeth. The crown wheel and pinion look fine. There is no excess backlash or tightness and the bearings all seem to be OK with no obvious rumbling or roughness. I had expected to see or feel something significantly wrong like a broken tooth or misaligned cog but there is nothing obviously wrong. Does anyone have any idea why my differential is behaving as if it is limited slip on one side only? 😟 Thanks Richard

Just to confirm that the service from Rimmers was excellent and the replacement steering bush arrived first thing yesterday morning. It fitted perfectly and the car is now back on the road and I will be taking her to a local car show this afternoon. Richard

That's very kind of you, Roger. I'm hoping that the replacement from Rimmers will arrive tomorrow and that this one will be the correct size but I'll let you know whether it's going to fit as soon as it arrives. I'll be in contact. Thanks Richard

Thanks Roger I don't have a reamer but if the new one that is now being sent is as tight as the ruined one, I will definitely find a way to increase the internal diameter before fitting it. Richard

This morning the two new steering bushes arrived for my GT6 from Rimmers. I went for the old style rubber bush as the newer poly version is out of stock. One fitted perfectly onto the shaft but the other felt much too tight and simply getting the shaft to slide into it required a huge amount of force. As soon as I fitted and turned the steering wheel it just ripped off the rubber locating nubs and now the entire bush is simply rotating in the outer casing. If the locating nubs had not ripped off the steering would have been mightly stiff. It's fine now but totally useless as the rubber will probably last 100 miles before it is completely shot! I've requested a replacement form Rimmers but it looks as if this weekends car show will be a no-show. 🙁 Richard

My plan is not to refit the electric fan if I can possibly avoid it, although until we get some really hot weather I won't actually know. If I do have to remount the fan, I will make up some proper brackets rather than use those plastic ties. Rixhard

Another update ..... I actually collected the radiator on Monday as the guy managed to do the re-core a bit sooner than expected. Before the re-core, there was a 3mm gap at both the front and the back of the frame between the frame and the core. They managed to fit in a bigger core which, I think has an extra row of tubes or perhaps just larger tubes, so that although the rad is the same size, both gaps are now gone. They also said that the old core was rather slimy and messy but not actually blocked as far as they could tell. I had drained the radiator into my large pan without losing any coolant but when I came to pour in back in I was about 700 mls short of coolant which I had to top up. I think this is due to the extra capacity of the new core. Anyway, I took it for a high speed run this afternoon and then let it idle for 10 minutes or so and the temperature did not even reach 80 degrees which suggests that the thermostat was opening and closing and the cooling capacity was never actually reached. The issue could well be that it is around 8 degrees cooler today than it was the last run but we seem to be heading in the right direction. Richard

An update. I took my rad to Motorads in Redditch http://www.motoradsonline.co.uk/ which was recommended by my Son. Andy, the chap on the desk, was extremely helpful and asked if I could wait whilst he took it off for some quick testing. When he came back he said that it was in pretty good condition and, although it was not operating at 100%, he was used to seeing far worse and would be surprised if the rad was the only issue. We then talked about all the other work I had done and the symptom that whilst the car was moving it all seemed OK but after I came to a halt the temp started to creep up. His view was that I had done what was needed and that he also agreed that the rad now seemed to be the weakest link in the chain. I did tell him that the Kenlowe did keep the temp down but he stated that they did not recommend after market fans and would not fit them because they caused other problems which, at this stage, he did not elaborate. His view was that with my cowling in place, an electric fan should not be required. By this stage, Andy seemed so reluctant to actually accept the business that I was beginning to wonder if they had too much work on. Anyway, once we had reviewed all the options, he agreed to recore the rad but said that they were fairly busy so it would take a while. Here we go, I thought, so how long I asked. About a week he replied! Good grief .... I was thinking in months! At this stage another chap walked in with a rad from a TR4 which was also fitted with a Kenlowe still in place. He said it seemed to have suddenly started leaking and could Andy take a look. Andy did that whilst me and the TR4 man chatted. Andy explained that the plastic tie fittings for the electric fan had vibrated against the core and worn it through and it was now weeping. He said that they get a lot of rads in with exactly this problem which is why they do not fit fans using the plastic ties and that he could repair the leak but would give it back without the fan fitted as they did not keep any of the ties and the owner would have to re-fit it himself. Andy advised that he should get some brackets fabricated if he really wanted to retain the fan. Anyway, there's quite a bit to think about there. I'll soon be £250 lighter so let's hope that it does the trick. Richard

Indeed so. I checked the input hose and the output hose with my hand when the car was idling after my test run and the temperatures are too close which is why the temperature continues to creep upwards. I've decided to speak to the specialist rad company used by the restorers that my Son works for and see what they can do. I'll let the forum know what they suggest. Richard

Thanks Ian. I wondered why the rad has two inlet tubes as I've never seen anything like that. If it is simply to get more flow into the rad then I agree with you that it suggests an element of desperation by the Triumph engineers. I will knock up a front cowling as you and others have suggested. The problem with the rear cowling is that the crankshaft axis is not actually in the centre of the rad but set over to the nearside. I don't understand why this is the case but it does mean that there is some "wasted" matrix on the offside. The limiting factor for a simple circular cowling design is the clearance to the water pump boss. I measured it all very carefully and have ended up with a clearance of about 3mm to the inner section boss. To cover the wasted matrix and still avoid the water pump would require a considerably more complicated fabrication. Richard