Well Bumbazor, I repeated your test and found both of my driveshafts were running out by about 2mm. Not excessive I suspect but to eliminate this as a source, I fitted two jubilee clips to each one with the screw section (the heavy bit) opposite to low points.

This is a tried and tested method of propshaft balancing in classic car circles, though it takes a lot of trial and error to perfect. It should compensate for the runout to some degree and therefore be felt on the road if the runout is the cause of the vibration.

The fact that I couldn't detect any change, either better or worse seems to suggest this isn't the cause on my car. There is some play in the nearside rear wheel bearing and my son was in the back the other day and could hear it rumbling. I can't being a deaf old sod so thought it was unlikely to be bad enough to vibrate - but maybe it is................

 

Time for my update now, after two days of constant results.

Previously, and you'll probably guess why I am mentioning this, I had first suspected the wheels. As I was getting whole car vibration I swapped rear wheels with the front, expecting to transfer the vibration to give steering wheel wobble. There was absolutely no change, and since I had a nicely steady steering wheel and steering, I ruled out all wheels at that point. Even more so when I took the rears off and had them balanced.

As time went by I tried various things when I could - driveshaft, jurid couplings, rear wheel bearings. Nothing seemed to make any change. Although when I did the bearings I did the pivot pin bearings too and I'm glad I did because one side was absolutely dry and almost seized. Anyway it wasn't those, but at least I had done them (the hardest part was knocking out the old ones - I made a tool out of metal to drift them out) so I still felt I had achieved something.

Shortly after I took those videos I got the tyres changed because they were too worn for my liking. After the balancing I had a couple of rides to and from work (~11 miles each way, mix 30 and 60 roads) and could have almost believed the vibration had gone if I had not been really looking out for it, or noticing things wobbling in the car. It puzzled me because I had previously ruled out tyres and balancing and the problem had almost gone; at that point it seemed to undo my previous thoughts about the wheels and put them back to the forefront of suspects.

I wasn't completely at ease though - some slight vibration remained, about 20% at most of the original. I then had a nearly 400 miles round trip last weekend and oddly I hardly noticed any vibration. Previously at 70, it would at times have been quite bad but this time is was a lovely ride.

I really couldn't understand how my initial non-suspicion of the wheels had been false; the first thing I tried - the swapping and balancing - made no difference and I would have expected some improvement, however slight.

During the week before the long trip I had ordered some UJs for the half shafts as that's where I left the troubleshooting before. They remained unfitted until last Sunday.
Following the new UJs and another couple of short trips to work and back I can honestly say I can no longer detect the vibration at all.

So here I am now, having replaced a lot of stuff I probably didn't need to, but in any case I don't begrudge it because I know I have a load of new parts and a vibe-free car.

Now my next problem is finding some thicker camber adjustment shims.



As for your rear bearing - is the play side to side, and can you or your son hear or feel anything when turning the wheel manually?
Does the behaviour (sound, vibration) of the car change when cornering? Sometimes a dodgy wheel bearing will exhibit better or worse behaviour when relieved of or subjected to load, but you probably know that already.

 

I am posting this again for anyone who finds this thread looking to cure vibration issues.

The Hunter Road Force Balance by an expert tech is the place to start when trying to cure vibrations in our cars. It will identify most issues, including your bad tires and will save you a lot of chasing ghosts and replacing parts trying to cure the problem.

Not trying to rub it in, but I know how sensitive our cars are to wheel/tire issues and conventional "balancing" does not do the job properly.

Try the simple, inexpensive things first before you start looking elsewhere.

In your case, all of your tires had issues and swapping them from front to back made no difference. A good Hunter tech would have found this right away and saved you a lot of time and money.
Vector

 

Thanks for the comprehensive update mate. I'm glad you have finally cracked it.


As for my bearing, I couldn't spin the wheel fast enough manually to hear or feel for roughness. Even with the gearbox in N there is still quite a lot of drag.


I had an operation to remove a spur of bone from my left elbow yesterday so won't be able to do anything now for a few weeks, this is why I bought the Jag in the 1st place. I figured an auto would allow me back on the road earlier and if your going to get an auto, what better than a Jag?

 

I have just had a look and the nearest Hunter Road Force Balancer is 52 miles away from me. I may pay them a visit once fit.

 

Hi


I have finally found the cause of my vibration. One of the bolts holding the prop to the rubber donut at the diff end was loose.


This must have allowed the rubber to distort and move the prop off centre enough to be out of balance. I tightened it and hey presto the vibes are no more.


Happy days.......

 

Those flexible couplings were one of the first things I checked on mine. I noticed they were in need of replacement so I didn't mind replacing them whether they fixed the problem or not.

Did you notice any cracks in yours? It is probably not easy to see when they are fitted though; when mine were off and I manually stressed the rubber they opened up and were hard to miss.

 

Hi ho Freebird,

A subtle, but easy fix. Thank you for letting us know that you solved the issue.

 

Hi

The rubber looked fine in situ so if it ain't broke.............

What I did do while I was under there was top the diff up - what a git of a job that is - the filler is too close the fuel tank to get a bottle of oil up there, I got more down my sleeve than in the diff.