'Drumming' Vibration at speed

[rogerc]

Since replacing the rear suspension bushes and mounts with polypropelene versions, I am noticing a distinct vibration from about 50mph upwards.

It vibrates up through my seat, and the best way I can describe it would be to call it a low 'drumming' vibration.

I used to get a degree of noise/vibration before the bushes were changed, but I don't recall noticing like I am now. Perhaps the rubber ones absorbed it more?

I've checked the obvious - the bushes are torqued up correctly. All washers, spacers, etc are present and correct. Prop and driveshafts are all secure on the flanges. Diff has oil in it... Draftshafts have grease on splines - no locking or sticking issues being experienced.

Had all four wheels balanced - they were in need of re-balancing but it hasn't improved the situation.

I'm wondering:
tyres (they're all different and of various dupious makes), wheel bearings, balancing on driveshafts/pro...?

Any suggestions - or more usefully, methods of tracking/determining this one?

I'm considering taking it to a specialist with a rolling road - can they trace this sort of problem? If so, anyone have experience of a good one in South East London/Kent area?

[Kevin Garrod]

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You could try changing the radio station

seriously though it could be your tyres, i once owned an opel manta that had old tyres, the tread was good but they had distorted and it sounded like there was a helicopter flying above me on the motorway!

eventually one of the head bolts vibrated loose with predictable results!!

could be a good way to loosen the notoriously stubborn stag head bolts....or not!!

good luck

[Andrew S]

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Hi roger

If you can see my email address, please drop me a line as i have been trying to resolve my vibration problem similar to yours and i have made a word document that lists what i have done to try and cure it and it may help you.I am happy to share it with you

Cheers

Andrew

[rogerc]

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Andrew,

I can't see your email - I think it needs enabling under your profile settings.

Anyway, I have enabled mine - if you click on my name in the left pane, one fo the options is to send an email.

I'd be interested to see what you have tried - like you say, lets share notes on this.

Thanks

Roger

[rogerc]

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Update.
I got a second-hand diff ‘cheap’ – I’ve now replaced the klunk with a whine…!!!
Question about the output shaft on the auto box.
There is visible play in this shaft when I push up/down on the front prop U/J. Is this normal, or is this another potential cause of my vibration?

I also have slight play in the drive shafts – but again I’m no expert so have no point of reference for what is acceptable.
I think my plan of action is going to be:

• Replace all four tyres (they’re old, different makes, etc)Replace drive shaftsReplace bearings

All subject to the two great factors – time & money of course…!!!?

[SteveP]

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Roger
This may be of some help, one of the problems with my Stag when it went in for its service last week was a drumming/vibration at 50mph that dissapeared when reaching 75ish. To investigate the problem, Faversham Classics swapped out my wheels for some others which confirmed the tyres (which were pretty old) were causing the problem - 4 new tyres and its a different car now! Interestingly, their recommended tyre is a Nanking 185HR14 which I hadn't thought of until talking to them.

Regards

Steve