Is the Jaguar prop much diffrence in length 
Up on the ramp again today. The Daimler prop is 55.25" flange to flange. We removed the spacers under the centre mounting and made sure it was straight but no joy as still vibrating. The mounting holes in the centre mounting plate have been ovaled which suggests it has been messed with. Fitting new bushes seems to have caused the problem as now there is no room for movement?? I am going to take the shaft off another Daimler and see if the shaft itself has been damaged somehow. Not looking forward to that without a liftā¦
Can you jack up the rear on axle stands and run the car in gear to observe underneath? You may be able to see if the propshaft is flailing around. Obviously take extreme care. Canāt see if youāve checked the adjustment of the stabiliser yet.
Not done the wheels off the deck but there is no movement in any of the drive train. I did release the stabiliser before readjusting.
I have noticed on my spares car that the centre support has very large spacers which brings the support plate much lower down.
By running the car on axle stands you can observe if the prop shaft is doing anything strange, like an elliptical movement.
Canāt see how spacers would make any difference; thatās the point of having UJās, to take up angular displacement. Are you 100% sure the yokes of the drive SHAFTS (plural) are lined up correctly? Thatās what this sounds like.
Yes yokes are lined up. Everything marked before removal.
Perhaps you could remove the shafts and have them checked for balance. I donāt think going to a single piece prop is the answer; Jaguar would hardly have gone to the complication and, especially, expense of the split system without good reason. Did you have the roadwheels off at any stage? Wire wheels? Any possibility the cause may not actually be with the propshaft?
Iām sure many āqualityā cars of the time used split shafts but the only other car I have owned which had one was my Sunbeam Rapier, which had the same problems and which I could never solve.
I think only the auto (BW35) version had the split shaft, so maybe it has something to do with that but it doesnāt matter anyway.
WITH CAUTION I would chock the front wheels and jack up the rear of the car. Remove the wheels and support the weight of the car on the rear axle (to keep the axle still) and run the transmission up to the point where you get the vibration.
If you donāt get any, looks like itās a wheel doing it although I have never known a wheel to be so out of balance that it can be felt through the inertia of the heavy back axle.
If you do, get a paint brush with white paint (or some other marker) and offer it up to the shaft in different places. If you get marks on part of the outside but not all the way round itās out of balance and heavy where the marks are.
Very crude I know but youāve tried all the āproperā ways 
It was only the autos that used the split shaft, but the BW DG box also used it. If wire wheel, maybe not seated on the spline correctly, long shot, I know.
They are wire wheels but only the fronts have been taken off to fit new anti roll bar and bushes. I think any problem there would come up the steering column but no steering shake it comes up through the car. It starts at only 20-25mph.
I am thinking off jacking up the rear just to see what is going on but I have a gravel drive so not ideal for this work. (never, ever have a gravel driveway). I took off my spare prop yesterday with just enough nose clearance under the car so not a happy job. It is rusty but maybe will solve the issue for now.
Seems I am 100% wrong here. I just checked my service manual, and it says that adjustment is critical. I guess if itās not right, the front uj will always be operating at an angle. That may not be an issue if there were 2 ujs, but there is only one on the front shaft. I donāt know much about Hooke Joint theory, but does the effective length change with rotation? I know the velocity changes with angular and rotational movement, and can be calculated by people cleverer than myself, but if the length changes (even slightly) and is constrained by the centre bearing, that would set up some kind of vibration, perhaps. 2 ujs on the same shaft would cancel that out, but thatās not the case here; they are on separate shafts. So, have you set up that 9\64" gap as per the manual? Itās a small measurement, so may be important.
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The centre bearing is mounted to the front propshaft, and perpendicular to it. It must be fitted parallel to, and directly in line with the gearbox flange in both the side and plan elevations, or the bearing will be twisted in its mount, which will apply thrust loads to it and lead to itās early failure. Hence the focus on correct alignment in the service manual.
As regards the comment "So, have you set up that 9\64" gap as per the manual? Itās a small measurement, so may be important."
I have rechecked my manual and cannot see where this is mentioned??
It would be quite difficult to see where the front prop is as you say straight against the gearbox flange. If the measurements are so critical then I am bemused why all the engine swops/rebuilds have not led to many of these issues. I have not come across this problem in the forums. It will be on the ramp today and we will try again. All I can do is use the jig to align the shafts vertically and horizontally. If that fails we will swop over the complete shaft and centre mounting and see if that changes anything.
Hereās what my manual has to say about it
Ha! Uploaded in the wrong order! But hope itās some help
That is what I am working from. I made the jig from timber and checked it against the ramp upright for straightness.
We just replaced the whole prop shaft with my spare one.
This one had four spacers above the centre plate. This made the front shaft go up at an angle to the gearbox. It still vibrated. We removed 3 spacers to bring the centre plate higher and it was still not level with rear section but I tried it anyway and itās horrible. Horizontal alignment was spot on.
Too hot to do more today.
I will remove all the spacers and see what happens later.
We cannot move the gearbox down as it has new spring and rubber in support plate. No adjustment unless we use spacers above the gearbox support but then we are adding further complication.
I seem to have wrecked a good car by replacing rubber mountings.
Also we checked the front tyres for roundness and found a small ovality. Not sure if it is the tyres or the wire wheels at this stage but it would add to vibrations within the car.
I have now got the car jacked up with no wheels attached and run her to see what is going on.
Please look at these vids on Youtube to see the results.
The discs are making a noise as it has not been on the road for a while. At tickover there is some noise and vibration but no obvious problem with the prop shaft alignment that I can see. When I increased revs to 1500 there is a lot of rumbling and vibration. Most of the noise appears to be from the back and around the axle but itās may be travelling through the body. Note that there was no problem with the car before we replaced engine mounts, gearbox mount, centre rubber mount and stabiliser. The UJās were checked and no play was found.
Clearly something is amiss but I have no idea at the moment what it is.
Idling speed: https://youtu.be/yZ-zt9HLTac
1500 revs: https://youtu.be/NcbWJy2MJxQ
Rattling from rear end: https://youtu.be/SiDzXlLKL74
Youāve been working on this awhile and must be frustrated. I donāt know whatās wrong with your car, but Iāll share a couple of thoughts:
Is the second shaft you tried known to be good - did it come from a driver with no vibration? If the driveline shop didnāt get the balance right on your first shaft and the second one is bad too, you might still have a balance problem. Perhaps you could try a recheck or a different shop? On re-reading your notes, I canāt tell if you used a specialist driveline shop, and I suggest you do that if you havenāt. I didnāt see that you mentioned the center bearing, but that can go bad and make ticking and grinding noises (like on my mk2, can fool a guy into replacing wheel bearings or brake discs) that are hard to localize. I think that bearing would be hot if itās going bad. Iāve replaced a few U-joints in my time, but have started having my trusted driveline shop do them after they have noted some subtle problems that I didnāt pick up. I do everything on my cars from paint to engine rebuilds, and I think U-joints are a pia.
My basic approach to problem solving is to assume it was the last thing I did that caused the problem, and to ask myself if I am making an assumption that might not be valid. Hang in there - youāll find it.
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When you replaced the universal joints I presume you made sure that they went back the way they came out?
If the joints get rotated by 180 degrees that will often cause vibration.
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Guys, I didnāt change the UJās as there is no play in any of them. The centre bearing is also tight (no play). I have removed the new rubber mount from the original prop and am cleaning up all parts. I will replace the new parts with clean everything. (garage/shop does not clean anything!).
I have a dial indicator now so can check run out on the prop.
Weather looks good for another day so will do this.
I am thinking I can remove the rear shaft and eliminate the front shaft up to centre support as a problem??