tail shaft vibration

[roadster]

Hi have had a vibration which seems to be coming from under the seat when doing above 80 kph.The tail shaft has been balances twice and the vibration dos.nt seem to be coming through the steering wheel so I dont thinks its tyre balance.
I have a 4 link rear suspension set up and I originally set it up correctly but I 'm wondering if the angle is out now.I do have two adjustable rear bars that I could use to change the angle.What do you think
PS: The uni joints are all good
The car is a 32 ford roadster

[34_40]

If you suspect the driveshaft angles then you need to verify those measurements. No sense guessing at it!

While you're there, verify the tailshaft bushing in the transmission haasn't worn excessively. As well as the universals.

.

[cffisher]

you could have a bad tire I have had that happen while chasing a viberation in new cars.

[roadster]

you could have a bad tire I have had that happen while chasing a viberation in new cars.

you could be right about the tyre but I would have thought I'd get it through the steering unless it is one of the rear tyres.The car has only done 1200 kms

[vara4]

I was gonna say the same thing, I got a air bubble under a steel belt and it shook like the drive line.
I had a friend driving behind me and said he could see the tire come up off the road because it was egg shaped.
This is not a four wheel drive is it??? We just pulled a front drive line on a buddies truck because of his universal joint.
It could also be a wheel bearing going out. Probably on the back since your not feeling anything in the steering wheel.

Kurt

[M.T.]

Un likley but dont forget about your axles... I had a slightly bent axle several years ago. It didnt start acting up until high speeds. Check everything that has already been mentioned and if that doesnt fix it take a look at the axles... Just a thought.

[jerry clayton]

Its the convertible top flopping!!!!!!!!!!

[roadster]

who said I had one

[34_40]

Just a bit of sarcasm from our friend Mr. Clayton..

Have you found the problem?

[roadster]

yeh thought as much.Hav,nt had time to look to be honest but I need to sort it out as it,s a pain when on highways,One of those jobs that you keep forgetting about until it happens again

[jerry clayton]

not sarcasm at all--------------haven't any of you ever noticed any thing flopping on a car in front of you on the road???????????


And I looked at your pics and saw a convertible top---------------

[roadster]

No your right the convertable top does flap a little bit but the vibration you can feel is coming from below.I have driven the car a few times with the roof off and it still produces the same vibration,but thanks anyway

[36 sedan]

Have you checked the motor and transmission mounts?
I had a bad trans mount cause vibrations at hard acceleration and hi-way speeds.

[JL350]

A good way to find these things is a run on the dyno. Can see what is vibrating at the road speed without the car physically moving. A friend found two bent axles after replacing lots of stuff in the drive train, two minutes on the dyno identified the problem

[roadster]

Have had a bad experience on a dyno a few years ago.But I can see what you mean