philoldsmobile

I (as have many other thirdgens) have a slight intermittant vibration at about 75mph.

So far i have drawn a blank, but may have found the answer. On perfectly smooth roads, the car does not vibrate at any speed, but if you go over ripples in the road, a cyclic yibration starts (best discribed as a faint "shivver") the car vibes, then calm, then vibes.

A lot of people have sugested fitting an ali driveshaft (Felix did this, and his vibe moved from 90 to 120+) as a way of moving the vibration to speeds above those that you drive at.

I have noticed the tail shaft has a little play in it, (not enough to cause a fluid leak though) I have since been informed that the tail shaft has an extention housing on it, held on by 4 bolts, and this housing has a bush in it. obviously, replacing the bush would remove the play.

Is it possible that this play is causing an "off ballance" situation in the propshaft, causing the vibe. (the lighter ali shaft would not go so far out of ballance, thus reducing the vibration)

What do you guys think? has anyone changed this bush? how difficult is it to change?

Thanks, Phil.

erictheviking

Are you talking about the torque arm bushing?

philoldsmobile

no, the actual bush (might be a bearing) that the tail shaft of the gearbox rides in.

ZZ42Fast

iTrader: (2)

I feel your pain... I had my rear wheels jacked up the other day and ran the car in gear to about 100mph and I could see definite vibration on the drivers side rear wheel- the offside was as smooth as a Cashmere Codpiece Have to rebalance that wheel and see if that does the trick (yeah right, nothing's that easy)

My tail shaft has a little play in it too, I guess it is normal. Then again you may want that confirmed from somebody who's car doesn't vibrate

I would portion the blame to the poor driveshaft's. I would get it balanced by the pro's. Has it always done it? If not, could be the tyres.

Cheers

RMK

Felix,

What did you hold the car up with? More than a couple of jackstands I hope. I would have a fear that the car would vibrate itself off the jackstands and uh-oh

ZZ42Fast

iTrader: (2)

Rob,

I know, me too! It was at Autopontiac whilst MOT'ing. They have the ramps that use 4 points to lift the car. We just used the back 2- steady as a rock...

Felix

RMK

That's ok then, but I'd still be worried. Keep us updated on the wheel balancing. Will be interesting to see if that cures the problem.

philoldsmobile

Felix, i'm pretty sure its not the tyres, but have suspicions about the propshaft. Reco prop is only 15 miles from me, so i might have the prop out, and have new uj's and have it balanced soon, it can hurt!

(plus its not expensive)



Still debating on changing the wheels, i like the rally wheels, but feel they have a little more of a "classic car" look than i'm aiming for.