Clanking propshaft and vibrations

[ericbeaumont]

Volvo OE clutch and OE release bearing, plastic ball cap thing (thanks TonyS9) and rear main oil seal replaced and the clutch is lovely. After a mile of every trip since, the usual Rolls is taken over by three gremlins which emerge slowly and become more obvious after half an hour of driving:

1 At idle a cyclical, fine vibration creeps through most of the car, esp. the steering wheel, seat etc. Disappears when moving off.

2 Above thirty deeper, persistent, prob. propshaft vibrations develop. By fifty the noise is quite obvious. I go no faster.

3 Below ten I can hear the back end of the propshaft clanking like a stick run quietly down a railing; as the car slows so does the noise. If I coast from twenty I hear the clanking more clearly. It clanks slowly in reverse, but not always.

Natural thoughts are that the propshaft wasn't marked and replaced correctly (though I can't believe that's likely); the gearbox was replaced and woke up another problem; gearbox or engine mounts are on the way out; a mixture of all three.

The work was done by reputable Volvo independents and the clutch work is fine. I'm already looking for a large sheet of cardboard to lie on and the road outside is good and damp.

Any suggestions? 945 230FK turbo, 168K, had a towbar in the past.
Thanks,
Eric.

[Joe of Loath]

Before doing anything drastic, check your exhaust. I knew I had a hole in my exhaust already, so when I heard clanking similar to how you describe under the anaemic roar of a well worn exhaust, I feared the worst.

Then I got a friend to kick the tail pipe while I lay under the car, and I realised that the exhaust had let go completely and was knocking against the bottom of the car. I'm sure it could happen to an exhaust in good condition if a hanger let go.

[aardvarkash10]

Natural thoughts are that the propshaft wasn't marked and replaced correctly (though I can't believe that's likely)...

The work was done by reputable Volvo independents and the clutch work is fine.

1 - I can believe its likely
2 - Even reputable workshops get it wrong sometimes.

Take it back to the workshop. If they ARE reputable, they will look into it and resolve the problem. At the least from a reputable workshop I would have expected they would road test the repair - if they had done so they should have noted the other issues and advised you.

[TonyS9]

I've had cars back from the dealer not road tested with clear defects. Time pressures, no quality sign-off system, inexperienced trainee etc etc. Mind you that was a long time ago with my parents cars, never used them myself.

Light vibration that is not related to road speed, regular clanking, is this also not perfectly matched to road speed? I'd bet on exhaust loose.

[ericbeaumont]

Joe, the exhaust is a year old and spot on because I did it myself. Aardvark: Yes, it's going back at the first opportunity (Thursday). On the face of it the source of vibration seem pretty straightforward: propshaft, but having read all the threads on propshaft vibrations it seems that other parts come into play - prop bearings and the differential and all sorts.

To be fair to the mechanic, he did test-drive it but probably only far enough to confirm all was well with the clutch. That was unlikely to have been long enough to hear the prop clanking or steering vibrations, which creep in after a mile or so.

That fade-in suggests its to do with movement of a part that settled when parked (rubber mounts?) or an expansion of warming parts. I found an article on the IPD site Technical articles - Driveline Vibration (10033) which suggested that the centre support mounting could be out of alignment, or Vibration At Idle (10066) which offers exhaust, transmission alignment, and sagging engine mounts (they also say catalyst, but unlikely). Throw in the prop UJs and a few others and it gets interesting.

I'd put up the link but I can't see a button on here to do it. Any idea?

[ericbeaumont]

Tony, the clanking is definitely related to the prop and slows as the car slows even when out of gear. It wasn't there before the clutch change so something has moved.

The vibration at idle I might put down to ageing gearbox mounts, and there's been oil down there for years from old engine leaks. Engine mounts ditto; leaks cured in my ownership but mounts must be original.

The vibration at speed suggests prop not refitted correctly.

Thanks for the input.

[bluebrickrick]

Just nip round your wheel nuts first, I chased a clanking transmission noise from Norwich to Truro, only to find it was the nuts on the nearside rear not pulled up properly, not loose but enough clearance for the wheel to move over the studs.

As for the static vibration, that has the hallmarks of an eccentric or swashing clutch or plate. As above, best returned to garage for rectification.

Rick

[TheLeeds]

I had a load of horrible knocking from under one of mine. I'd just about concluded it was the propshaft support bearing, but when I got under there to have a look, the noise turned out to be a completely shot gearbox mount. I confirmed this by getting hold of the front part of the prop and pushing it up and down. Same noise.

A replacement was £7.11 from ebay.
When I took the old one off, I could see where it had been making metal to metal contact, and a lot of the rubber had disintegrated.

New one fitted and silence reigns again, although it took longer to jack the car up and support it safely than it did to change the mount.

http://www.ebay.co.uk/itm/391328498103?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[bluebrickrick]

Eric, another thought, I had what seemed like a hundred miles of what may have been polypropylene washing line manage to wrap and wind its way round my propshaft, wedged up in the tunnel, tore out the handbrake cable and jammed me up solid - (absolute nightmare trying to cut it off in the dark & sleet)

It knackered the middle bearing too and when re assembling I think the propshaft sliding splined shaft joint had a couple of arrows punched on to match the splines up - (there was what appeared to be a balancing patch welded on one section) - it rattled badly until I realised this and put it back correctly.

£0.02

Rick

Some days we are the pigeon and some days the statue, today has been a statue day

[ericbeaumont]

End of the story: the clanking and prop vibration was resolved after they had a look on the ramp: when the propshaft was bolted back after the clutch change, the rubber ring in the centre bearing slipped out of place. Five minute job to fix.
Running peacefully now.
Thanks for the tips.
Eric.

[bluebrickrick]

I once chased an apparent transmission, speed related 'stick rattling' which turned out to be a wheel where the nuts were not obviously slack but not fully torqued up, so the wheel was moving relative to the studs - just a thought if the sensible stuff doesn't find the culprit ;)