2002 td4 wobble after carrier bearing replacement

Hello,
Wondering if anybody may have experienced this or have any guidance to my freelancers new little problem…..
So a while back had a grinding noise coming from the car, thanks to the guys on here successful diagnosis as centre prop shaft carrier bearing (on my 2002 td4) bearings replaced by the local garage and noise all gone yay! However have now noticed I’m getting a balance type vibration coming through my seat between 40 - 60 mph ish, below or above that all nice and smooth. So, put on my investigation hat and had a look underneath at what’s been done, I can see both centre bearings have been replaced and can also see visible markings on the front and reap props where they join the VCU, I’m sure this was the garage doing the right thing by marking how it came apart to avoid this very thing lol. I’ve also spent today adjusting the vcu damper (read that from here) to see if that might have sorted the wobble but no joy. Had the rear wheels balanced still the same so just wondering if anybody else has had any similar experiences or ideas on how to resolve. It’s not a massive wobble but is noticeable and you do drive through it which is making me thing balance somewhere? I’ve also had a visual inspection of the prop shaft front and back and all the factory fitted weights seem to be there with no obvious signs where any have fallen off?
As always any help massively appreciated.
Cheers

Check bearings are at 90 degrees to vcu and vcu is aligned to centre of vehicle.

Bolts through slotted holes in bearings should be centred.

Thanks, I did check that and they were a bit out. Levelled them up so they are at 90 degrees, still the same. The bolts are not in the centre of the slotted holes but they are equal each side if that makes sense ?

I was wondering if the prop shaft could have been removed from the ird or rear diff and put back out of line as I can’t see any paint/pen marks on those areas?

Pretty sure the props can be installed in any rotation as they are balanced.

I don't know if this balancing uses weights on the shaft that could have been dislodged during the work. I doubt it as there are lots of threads here involving props being removed and reinstalled and few (none?) of props becoming out of balance (I believe).

Jamin77 said:

I was wondering if the prop shaft could have been removed from the ird or rear diff and put back out of line as I can’t see any paint/pen marks on those areas?

Click to expand...

Each propshaft section is balanced individually, so there's no need to mark anything or fit anything back where it came.

It's possible that some part has been bent or knocked out of alignment during the VCU bearings removal process.

Check to make sure everything is back together properly, and that all flanges and spline joints are correctly seated.
Also make sure the VCU is in alignment with the centerline of the vehicle at both ends, and that the damper is towards the rear of the vehicle, not the front.

Out of interest, does it have identical tyres all round, and are the least worn on the rear?

Thanks Nodge68,

I agree, is possible an extra large persuade-atron has been used…. Although I hope not…..
The vcu damper is towards the back,of the vehicle, I tried adjusting it today to no avail.
It has identical tyres fitted, I had them all replaced at the same time and the least worn are on the back (naturally worn slower)

is it a visual alignment of the vcu to the central or are there any indicators?
Also is there anything obvious to look out for things correctly seated, I’ve been under it all day and checked both ends couldnt see anything obvious…

was thinking the next step process of illumination could be to take the back half off and see if it still does it?

cheers….

Jamin77 said:

Thanks Nodge68,

I agree, is possible an extra large persuade-atron has been used…. Although I hope not…..
The vcu damper is towards the back,of the vehicle, I tried adjusting it today to no avail.
It has identical tyres fitted, I had them all replaced at the same time and the least worn are on the back (naturally worn slower)

is it a visual alignment of the vcu to the central or are there any indicators?
Also is there anything obvious to look out for things correctly seated, I’ve been under it all day and checked both ends couldnt see anything obvious…

was thinking the next step process of illumination could be to take the back half off and see if it still does it?

cheers….

Click to expand...

Just as a bit of an update here after months of faffing about finally bit the bullet and got hold of a new vcu…. Wobble gone yay!!!!!!

Only thing now is a bearing wine I think from cheap carrier bearings, will get a new set of FAGs on there hopefully then all resolved…

So good now it’s not wobbling