shudder at 50mph

[Dom]

Hi,
Ive read all the threads on here and followed the advice about vibration.
I have replaced a worn quill shaft with a new unit, replaced a prop-shaft with a new unit and replaced a drive shaft with a new one.
I now have a shudder/vibration at around 50/60 mph (don't want to take it higher). The tyres are new and they were fine before the shudder began.
When the vibration first started, it was unbearable at 30/40mph, the new items (prop & quill) have solved that and its as smooth as it can be until the higher speeds.
I noticed the rubbers on rear suspension are old, would this cause a vibration?
I have also noticed a difference in handling, it feels rather like driving a shopping trolley at times, drifts and twitches between gear changes.
The old prop was shot and the quill was leaking, all I seem to have done is eliminated the lower speed vibe and put the vibration up to the higher speeds.
Could it really be wheel balancing even when they were fine before?
Yours,
Confused.

[ChrisLD364]

Hi

With a vibration around 50mph always eliminate wheel balancing first. It even fixed my Land Rover 110. They needed a lot of weights!

I've had some bad balancing in the past from Quick Fit and the like with weights dropping off. I now watch it being done to be sure.

Chris

[richardthestag]

Also when they balance avoid balancing on the wheels centre hole. Pay the extra and get them to mount the wheel on wheel stud holes.

One know it all fitter told me i was talking rubbish, agreed that he would balance the wheel how he wanted. Remove it from the machine, put it straight back and tell me the balance was good, that had him scratching his head for a while. Then he balanced the wheel properly.

With yours though the shopping trolley feel sounds worrying. I might be inclined to check rear subframe mounts are tight and that the bushes are not shot. I got a huge vibration out of mine at motorway speed but that was down to rubbish ebay gearbox mounts that we made out of cheese

[4x4]

It may be that with so much other stuff replaced, there is now no "give" in the system to soak up what was there before.

My car had no problems at all with vibration until I had the oil seal and bearing in the diff extension replaced (because of an oil leak), then the car shook horribly. The propshaft UJ's (rear propshaft in my case) were shot. Once there was no play in the bearing to let it move around - the vibration was awful. Perhaps you have a variation on the same theme.