Drive train vibration

W

Willy Eckerslyke

Well-Known Member
UEY - the 2000TC that I've just put back on the road has a rather worrying vibration coming in at around 40mph.
So far I've driven it around 10 miles to the MOT centre and back yesterday during which I noticed some vibration and assumed it was a driveshaft UJ. It could be felt through the brake pedal too which was a bit odd. This morning I headed off to work in it but after about 5 miles it was feeling quite severe so I turned back, rebuilt a spare driveshaft with new bearings and inner UJ and fitted it, despite the old one not seeming too bad.
It made no difference.
Jacking up the rear wheels in turn and 'driving' in 4th had the vibration reoccuring, same regardless which wheel was raised. By pressing the brake while in gear, I could feel the vibration through the pedal, but not if I pressed the clutch right down too.
The propshaft UJs seem healthy. The sleeve on the sliding yoke was loose but tightening it made no difference.

So I'm at a bit of a loss. The clutch is starting to slip so will need replacing. I'm wondering if clutch could also cause this vibration, though none is felt when it's being used.
Any thoughts?
I need to use it this week so will just take it slow and hope it lasts until the weekend.
 
rockdemon said:
front bush and spacers on the diff extension housing?
Click to expand...
I had complelety overlooked them, so thanks. They are rather an oily mess, but would they really cause this much vibration?
I turned back this morning because it felt so bad I thought a driveshaft UJ was about to make a bid for freedom.
If I get to work and back OK tomorrow, I might try removing the propshaft and running the engine so that I can be sure if it's from the front or back.

Just had a thought - I had replaced the engine mounts for VW Golf items but hadn't realigned the gearbox mount. But again this sounds more severe than I'd expect from that.
 
Since this car is "new" to you, and probably has been neglected for years, i would suggest to start from the beginning and work your way through the entire driveline. I understand that this is not very convenient for you at the moment, but i am afraid there will be no shortcuts. My guess is that there are more than one issues and each of them is contributing towards the vibration. So, start from the engine - gearbox alignment, and move to propshaft, diff extension mounting, driveshafts, bad wheels and / or tyres. Is the propshaft itself properly aligned? You said that the sleeve was loose, so perhaps someone in the past took it apart and assembled it the wrong way. A propshaft "out of phase" combined with a bad diff nose mounting could cause some bad vibration.
Also please avoid to run the car with just one of the rear wheels in the air, you are wearing out the diff, and for God's sake don't try to brake at the same time! The diff will try to allocate torque to the wheel still on the ground and you know what comes next. :shock:

Good luck with it.
 
Thanks Demetris, you're right of course, the systematic approach is what I need to turn it into a reliable daily driver.
Wheels, tyres, driveshafts, DeDion and rear links are off my previous daily driver (MOT just expired) so should be OK. I ran out of time so just swapped them all over this last weekend. Just the one driveshaft was a little suspect hence today's work.
Thinking about it, I'd lowerered the diff to replace the brakes which would have put a lot of strain on the diff extension bush as suggested by Rockdemon, so that's definitely worth replacing. Besides, I have a nice galvanised mount ready to fit while I'm at it!

I'm still fearing the worst though - that the clutch is about to disintegrate!
So tomorrow I'll order a clutch kit (it needs one anyway) and that bearing. And I'll start working my way through as you suggest.
 
rockdemon said:
Yes the front diff mount will do that especially if it's an oiley mess
Click to expand...
I think you might have nailed it.
The drive in to work this morning was fine, keeping it below 40mph. But I noticed that rolling slowly down hill in neutral, holding it back with my foot on the brake, I could feel the sort of pulsing you get from a warped disc (though the discs are fine). I feel that this points to something in the area of the propshaft - that bush, misalignment, seized UJ...

The clutch is very much on its way out so will need attention anyway. Starting the car this morning resulted in a loud clatter like something catching a metal fan. Switched off immediately and had a look - nothing to see. Started it again with my foot on the clutch and it was fine and didn't do it again.
 
I have to confess I couldn't muster the energy to remove the propshaft this evening, especially as I'm planning to do the clutch at the weekend so will need to disconnect it anyway.
But I did reverse onto ramps and have a good look. I was wrong, the diff extension mounting rubber is actually quite healthy looking. :(
At the gearbox end, the snub rubber also looks decent, with the rod close to its centre. The spring is slightly askew, but not massively.
No doubt all will become clear, but at the moment I'm none the wiser.
 
If one of the brakes are dragging slightly, especially if there's a wear lip on the outer edge, it can overheat the disc and cause a vibration when traveling at speed.
 
testrider said:
If one of the brakes are dragging slightly, especially if there's a wear lip on the outer edge, it can overheat the disc and cause a vibration when traveling at speed.
Click to expand...
Thanks for the suggestion, but no, I isolated each wheel in turn by jacking up the corners and running the engine in gear. The vibration occured equally with each side in the air.
And the discs are good - they were already decent then I had them lightly skimmed to make them perfect. Calipers are recon units with stainless inserts; pads, hoses and pipes are all new, servo rebuilt with new seals, new master cylinder. I.e. the entire braking system is tip top.
 
OK, I've got it sussed!

I spent a very long yesterday renewing the clutch and that differential front bush and replacing the propshaft with a spare. The old clutch was down to its rivets and the entire bellhousing had a thick coating of nasty black powder. Crucially, the splines of the input shaft were all gummed up so the clutch plate wasn't sllding freely. I'm certain it had been dragging a little, so while braking with my foot on the clutch, there was still some forward drive fighting the brakes. Then those nicely skimmed rear brake discs - the fellow clearly messed them up as they're both slightly out of true.
The rear joint of the propshaft felt a little notchy, more like solidified, old grease than wear.
Gearbox alignment had been reasonable, but not spot-on.
I reckon it was a combination of the above that caused the vibration.

While I haven't replaced the discs yet, there's no longer any vibration when driving - just the expected pulsing when braking.

Lesson for me is not to dismiss new (or refurbished) parts!

Thanks for all the suggestions - it looks as if you were all correct to some extent!
 
You must log in or register to reply here.
Back
Top