Strange Vibration

[AndrewMAshton]

Hello All,

 

thought I had got away with a relatively trouble free outing, in North Norfolk this week so had a lovely run around and only a puncture and full beam failure to contend with, and so I thought, until the trip back to Ipswich via Lowestoft. When I set off there is a rattle that speeds up as the road speed increases, not everytime and not dis-similar to an exhaust rattle. I have done a thorough examination, all suspension bolts, exhaust fittings etc etc are fine, my big bar cannot persuede anything to move that should not move, and then, on the way home a vibration at 60mph, I first put it down to the spare wire wheel out of balance but noticed the vibration stopped when I lifted my foot off the accelerator. The only thing left is the prop shaft, which I have looked at and checked for play and all I can get it to do is rotate about 1/3" to 1/2" before the diff moves. I have gripped both sides of the spline and it appears in order.

 

All thoughts and ideas gratefully received as I after 6 years of TR ownership I am going to my first show at Lytham Hall in August.

 

Thanks in advance,

 

Andrew

[Guest ntc]

Hi Andrew

Check the diff mounts first

[AndrewMAshton]

Neil,

 

thanks for that, checked, all OK, new poly bushes this winter, after another, very thorough check the only wear I can find (apart from the play in the diff mentioned earlier), is a smidgeon of wear in the universal joint on the at the rear of the prop shaft where it joins the pinion flange, what I cannot understand is why the vibration should stop when I take my foot of the accelerator,

 

Cheers,

 

Andrew

[Guest ntc]

Neil,

 

thanks for that, checked, all OK, new poly bushes this winter, after another, very thorough check the only wear I can find (apart from the play in the diff mentioned earlier), is a smidgeon of wear in the universal joint on the at the rear of the prop shaft where it joins the pinion flange, what I cannot understand is why the vibration should stop when I take my foot of the accelerator,

 

Cheers,

 

Andrew

 

 

Andrew

Remove the prop and check the hole's have not gone oval and take it from there,your ? It will not be under load

Ps

Replace with new bolts

Edited July 29, 2010 by ntc

[RogerH]

Hi Andrew,

somebody posted something simlar the other day. Definate tap/rattle at BACK of car in time with road speed.

It turned out to be the FRONT disc pads.

 

Do you have a big bore silencer if so is it hitting the gearbox balance weight??

 

Rear wing/bumper attachment loose

 

Roger

[Badfrog]

Hi Andrew,

 

60 mph rang a bell in my head: check the UJs.

A single bolt or screw different from the others causes unbalance. This induces vibes when the propshaft rotates at certain speeds (60 to 80 mph).

On a given UJ, all bolts and screws must be absolutely identical. Between UJ, it's less relevant although I like a job to be thorough.

 

Badfrog, been there.....

[88V8]

... the only wear I can find (apart from the play in the diff mentioned earlier), is a smidgeon of wear in the universal joint on the at the rear of the prop shaft where it joins the pinion flange, what I cannot understand is why the vibration should stop when I take my foot of the accelerator,

 

I can't remember why, but vibes under acceleration = rear uj, under deceleration = front uj.

Might also be the sliding spline, although you've checked that..

 

Rattling noise, something else I think.

 

Ivor

[Badfrog]

I can't remember why, but vibes under acceleration = rear uj, under deceleration = front uj.

Ivor

 

 

Ivor,

 

It's caused by weight transfer under change of pace. Weight induces strain.

 

Badfrog

[AndrewMAshton]

Hello,

 

all fixed, as you said, rear u/j was shot, after much swearing and cursing and removing of caps as the rollers bearings wouldn't behave all back together, test run on the A14 and no vibration (well, no more than usual). Next challenge is to find a way to grease the u/j as I cannot get my grease gun over the nipple, probably have to fit an extention

 

Thanks again for your help,

 

Andrew

[kob666e]

Hello,

 

Next challenge is to find a way to grease the u/j as I cannot get my grease gun over the nipple, probably have to fit an extention

 

Thanks again for your help,

 

Andrew

 

 

 

If you contact these guys http://www.stephenslube.co.uk/grease_nipples.asp

 

and get a couple of these:

 

HUF4LL 1/4" UNF straight (29mm overall length) £ 0.86

 

it will make greasing your uj's a lot easier (check the thread in your uj before ordering)