Strong vibrations from 75mph up

[Guest]

Hi to all, I hope my English is understandable to the reader('s)...,.

I have a 71' (original 3.0, RHD manual with A-OD) Triumph Stag since 2009. After I bougth the car I transfered it about 400 Kilometer to home on the Autobahn. There was a HardTop mounted during the Autobahn transfer.

While driving/riding I noticed vibrations when running fast (more than 60-80mph, 100-140km/h), I thougth about the old tyres (13 years old and 3 different tyre types) or about tyre balancing. But it was not!

Over the last 2 years I have done many things, especially the following to reduce vibrations. I have...,
1. put new tyres (Vredestein Sprint Classic 185 HR 14)
2. balanced new Tyres on WireWheels
3. mounted new bushes (each end rear subframe arms, the big ones and changed the differential mountig bushes to poly)
4. new poly bushes to trailing arms
5. checked and excanged exaust hanger assembly and all rubber
6. changed all oil (esp. differential, gearbox/OD)
6. checked chassis frame and suspension

... no improvement to the vibrations. The Stag is a very noisy/vibrating car, isn't it? But I do not mean/complain the engine- and exhaust sound, that is fine!

Then further ...,
6. two new top mounting rubber front suspension, check everything else.
7. two new gear box rubber mounts and all rubber to the cross member
8. overhauled and balanced the propshaft and spent two new joint's

Status quo:
In my opinion the gearbox, the overdrive and the differential all work's fine, I can not feel any play in the ball bearing (gearbox end-bearing, diff front-bearing). The gear lever is nearly vibration free at any speed.
The two drive shaft's were changed from the last owner, there is a little play on inner axle shaft splines. Also a little play in the bearing's left and right of the differential, but no oil leaking...

Can anyone help?

My Experiences:
Only the two gearbox rubber took any effect! The old ones where bent and distorted, one is less high than the other (look at pictures, upper link's). The new one's rubber is very, very hard compared to the old one's, so I purchased not original silent rubber's out of German production. The rubber is very soft! I installed them to the car and the next ride showes less vibration's, I can drive faster than 80mph and the vibrations seem to be "normal". But they were compressed (when installed!) to 80% of normal high. I think this is not good!?!

Then Put in the harder gearbox rubber's (original, British-Passion-Shop on eBay, same as Rimmer I think so). Then I can not drive faster than 75-80mph. Over 80mph the vibrations to the auto body is extreme. Near 40mph there is also a muted vibration, but insignificant..., I think this is in the tolerance.

Forum problem, can not upload pictures?! Why? Foreign Web-Link?

Please look at http://www.cdfit.homepage.t-online.d...rboxrubber.jpg
and please look at: http://www.cdfit.homepage.t-online.d...ineMountLH.jpg -->Had to be changed too?

Pressing the clutch while driving 80mph increased the virbration, but repeating the situation will give different intensity...

That is much Info, not an easy issue!?! I think I have to change the gearbox rubber once more again to fit the soft version gearbox rubber's, or what is about the engine rubber mounts?

Many problems but a Triumph Stag is a beautiful design car,
regards from Germany
Claus

[StagnJag]

Hi Claus and welcome to the forum.

I had a vibration ad 80+ mph. It was the quill shaft bearing. (Between the differential and the propshaft).

Vibrations can also be caused by the fan's viscous coupling at the front of the engine. This causes vibrations right through the car. With the engine off, grab a fan blade and see if there is any forward/backward movement. Any at all and it needs replacing. It should also not spin freely.

Vibrations at 40/50 can be caused by out of balance or out of shaped wheels. Stag alloy wheels can be tricky to balance as most modern garages (In the UK anyway) use the hole in the middle to balance. The hole is not always perfectly in the middle on original Alloys. Also if the tyres are old, they can become misshapen and no amount of balancing will cure the problem.

That's all I can think of at the moment!

Rgds

Dave

[AlanD]

i dont know if this helps i had a rumble, vibration over 70mph, found out it was the rear wheel bearing, new one being fitted at the moment. Have you tried putting the car on axle stands and spinning them, and check for play too

Alan

[Stagdad]

[QUOTE=StagnJag;160153Vibrations at 40/50 can be caused by out of balance or out of shaped wheels. Stag alloy wheels can be tricky to balance as most modern garages (In the UK anyway) use the hole in the middle to balance. The hole is not always perfectly in the middle on original Alloys. Also if the tyres are old, they can become misshapen and no amount of balancing will cure the problem.

That's all I can think of at the moment!

Rgds

Dave[/QUOTE]


Think they are wires so this won't apply Dave or will it if the adaptors mount in the same way then it could still be an issue.

Cheers Steve

[new to this]

hi claus

you could also check the exhaust where it goes through the rear subframe arms you can get vibration there

thanks dave

[V Mad]

I dont think you mentioned the drive shafts? Maybe you have a bad universal joint or wear in the splines?

[Andy Rundell]

is the vibration definitely coming from the back of the car? if you can feel it through the steering wheel, based on what you have changed so far, i would suggest changing the front lower ball-joints on both sides and also the wheel bearings.

.......... Andy

[71Stag]

Hi Claus
I solved most of the vibration problems on my car also a 71 man o/d with a new gkn propshaft from james paddock and a new bearing in the diff extentsion housing, the bearing proved to be very worn when removed.

[Guest]

... many thank's to you all. The steering wheel has no vibration at all speed. The viscous coupling I have checked, it is o.k. too. I can feel a little rear play in drive shafts, but I think this is normal...

The vibrations that I can feel >80mph is much more than a motor drone / drumming noise / bearing noise. It is more like an oszillating mass..., I have to slow down the car otherwise it is very uncomfortable and I have fear to break something. Disengaging the clutch does not help, only speed reduction has an effect.

So I will dismantle the differential nose assembly to check the bearing and the quill shaft. Can I feel a defect bearing or quill shaft without of dismatling the diff nose? Only by strongly rocking motion to the propshaft? I did not find a play (jiggle propshaft) while the diff nose is mounted in the car.

2nd I will have a inspection of the rear wheel beraings and the both drive shaft's, dismantling them and will keep an eye on the UI joint's.

What is about the flywheel? But there are no vibrations when give rev's (accellerate) at standing car, no drive...

Regards from Germany
Claus

[flying farmer]

You say you have wire wheels fitted. If there is no steering vibration that rules out the front wheels. Try jacking the rear of the car off the ground by a small amount, if possible on the rear trailing arms so the suspension stays at its correct working height. Make sure that neither rear brake is dragging at all, then put the car in gear and run it up to speed. If one brake drags at all then one wheel will remain stationary while the other runs at double speed.
It is most likely a wire wheel problem
Wire wheels must be balanced located on internal and external cones, as these bear on the only machined areas of the wheel
If in doubt, try it with the wheels removed
One other possibility is that the diff nose extension is the wrong one, I believe two different ones were fitted which alters the angle of the front and rear propshaft mounting flanges
Another possibility is the propshaft. Do the front and rear universal joints align with each other? I ask this as when I rebuilt my TR 20 years ago I repaced the universal joints without seperating the two halves of the shaft, and was plagued with high speed vibration. It was only when another joint failed some years later, I realised the two halves of the shaft had been fitted one spline out. I don't know if it came from the factory like this, or it was done by a previous owner, but the vibration problem went away when it was correctly assembled
Neil

[Duncan Skye]

Hi Claus,

Vibrations can be the result of several out of balance forces working together to produce a result that you would never expect. This may be happening when you dip the clutch and the drive is taken up under different dynamics. I gather from reading your post that "the vibration to the auto body is extreme" and you don't want to drive faster than 75 - 80 MPH. This leads me to think that a wheel is imparting the vibration.

Sometimes a worn shock absorber will allow a wheel to 'tramp' up and down, sending a related vibration into the car. That vibration will be related to whelel revolutions and not engine and propshaft revolutions. One way to check for this would be to drive along and have another driver with passenger following you. If the following car moves to either side and the wheel is tramping, he or the passenger will see it. If a shock absorbers is at fault, replace both as a matter of course.

I hope that is of some help.

Duncan, Skye.

[Guest]

Hi to all, thank you for your helpful assistance.

Status Dez. 2011

I have found out, that the propshaft is the reason of the vibrations (99% most likely). I have not changed to a new one until now because of winter time, I will not drive until spring 2012...

Balancing/new ui-joints did not help because the balancer did not a good job. They have ignored the very little radial-play in the splines (shift piece, yoke)! Only did new lubricating grease in it and added a grease nipple. So I think the play is the cause...

When I install the propshaft with the splined-yoke to overdrive side flange (near the rubber mountings/gerarbox), then I can feel the vibrations at 75 Mph in a strong way. When I install the propshaft the other way round, splined-yoke to the differential side, there are very less vibrations any more. So I can drive faster now.

Solution: I will buy a new propshaft and let you know of the effects in spring 2011.

Regards from Germany
Claus

[Duncan Skye]

Hi to all, thank you for your helpful assistance.

Status Dez. 2011

I have found out, that the propshaft is the reason of the vibrations (99% most likely). I have not changed to a new one until now because of winter time, I will not drive until spring 2012...

Balancing/new ui-joints did not help because the balancer did not a good job. They have ignored the very little radial-play in the splines (shift piece, yoke)! Only did new lubricating grease in it and added a grease nipple. So I think the play is the cause...

When I install the propshaft with the splined-yoke to overdrive side flange (near the rubber mountings/gerarbox), then I can feel the vibrations at 75 Mph in a strong way. When I install the propshaft the other way round, splined-yoke to the differential side, there are very less vibrations any more. So I can drive faster now.

Solution: I will buy a new propshaft and let you know of the effects in spring 2011.

Regards from Germany
Claus

Hello again Claus,

Glad you've identified the source of the problem. I don't know whether you know this or not, but the propshaft flanges have alignment marks on them so that they can be matched up the same way as they were originally. That may not still be the case if any of the components have been changed by a previous owner, particularly the propshaft. In my instance, I could only find the alignment marks on the gearbox end of the drive shaft, so will have to wait and see what I have got once I get my car on the road.

With best wishes for a happy Christmas and a great new year,

Duncan, Skye

[V Mad]

I recently checked over my MOD propshaft and noticed that the splined section had a small amount of play. I checked the screwed collar and found that it could be tightened quite a bit, and after that there was very little play.

When this spline is loose it will result in an out-of-balance force, and if placed near the front, maybe the compliance of the rubber bushes will allow more movement hence more vibration than if placed at the rear which is probably of greater mass/lower compliance.

[Guest]

Hi To all, I have found the solution by changing the Propshaft to a completely new one, manufactured without the torsion damper (no rubber in the tube). Now everything is ok. Regards from Germany, Claus.