Vibration after an hour at highway speeds

[Zymurgy]

This happened last year when I drove to Nat's but my transmission and suspension were toast then. It almost feels like flat spots on a tire when they are cold but this happen after an hour after driving 70 plus mph.

Anyone think I could have a bad tire? They are new BFGoodrich Radial T/A. Just driving around home no problem and once I do get the vibration I need to drop to about 55 before it isn't noticeable.

 

[68Nwprt]

The last time a had a car with a vibration isolated to 45-55mph. It was a slightly bent wheel.

 

[MrMoparCHP]

Rotate the tires, this might help to eliminate tires or help isolate which one.


Alan

 

[Stormer]

Is the vibration in the steering wheel or the seat?

 

[Zymurgy]

Is the vibration in the steering wheel or the seat?

it's actually at the seat the whole car.

 

[bulldogchesty]

Maybe u-joints going bad.

 

[Zymurgy]

Maybe u-joints going bad.

I replaced the rear one and there really wasn't anything wrong with it, so I didn't change out the front.

 

[LocuMob]

I was thinking u joints when you mentioned dropping the speed it goes away.

 

[Zymurgy]

I was thinking u joints when you mentioned dropping the speed it goes away.

Would a u joint problem only occur after a long drive at high speed. I drove it over an hour yesterday around country roads 50-60mph. On the way home I took it up to 80 nothing solid as a rock.

 

[thrashingcows]

My wagon had a similar shake just after I started driving it. Would be fine for a while, then after about 30+ minutes of driving it would start to shake. Thought it was wheels, wheel bearings, U-joints, drive shaft angle, drive shaft out of balance...etc. I fixed, altered or replaced all of these things and it still would shake.

Can't recall where I came across my solution. Think it was a comment made on one of the C-body boards....an old thread I was searching through to try and find a solution to my problem. Anyway the person who posted up the comment mentioned that the 60's C-bodies had a 2 piece drive shaft. Not in the conventional "2 piece" with two drive shafts and a carrier bearing...but an outer, and inner drive shaft tube that are held together with rubber.

So I went out and checked my drive shaft. Sure enough I had the two piece drive shaft. The comment also mentioned that after so many decades the rubber inside the drive shaft begins to deteriorate, and then when you start adding heat it becomes less ridged and the inner, and outer drive shaft tubes begin to resonate and wobble at different frequencies....thus the major vibration.

So I had a new solid one piece drive shaft made, and have not had a problem since.

 

[rexus31]

My wagon had a similar shake just after I started driving it. Would be fine for a while, then after about 30+ minutes of driving it would start to shake. Thought it was wheels, wheel bearings, U-joints, drive shaft angle, drive shaft out of balance...etc. I fixed, altered or replaced all of these things and it still would shake.

Can't recall where I came across my solution. Think it was a comment made on one of the C-body boards....an old thread I was searching through to try and find a solution to my problem. Anyway the person who posted up the comment mentioned that the 60's C-bodies had a 2 piece drive shaft. Not in the conventional "2 piece" with two drive shafts and a carrier bearing...but an outer, and inner drive shaft tube that are held together with rubber.

So I went out and checked my drive shaft. Sure enough I had the two piece drive shaft. The comment also mentioned that after so many decades the rubber inside the drive shaft begins to deteriorate, and then when you start adding heat it becomes less ridged and the inner, and outer drive shaft tubes begin to resonate and wobble at different frequencies....thus the major vibration.

So I had a new solid one piece drive shaft made, and have not had a problem since.

After reading Mike's OP, my first thought was the drive shaft is out of balance.

 

[Zymurgy]

My wagon had a similar shake just after I started driving it. Would be fine for a while, then after about 30+ minutes of driving it would start to shake. Thought it was wheels, wheel bearings, U-joints, drive shaft angle, drive shaft out of balance...etc. I fixed, altered or replaced all of these things and it still would shake.

Can't recall where I came across my solution. Think it was a comment made on one of the C-body boards....an old thread I was searching through to try and find a solution to my problem. Anyway the person who posted up the comment mentioned that the 60's C-bodies had a 2 piece drive shaft. Not in the conventional "2 piece" with two drive shafts and a carrier bearing...but an outer, and inner drive shaft tube that are held together with rubber.

So I went out and checked my drive shaft. Sure enough I had the two piece drive shaft. The comment also mentioned that after so many decades the rubber inside the drive shaft begins to deteriorate, and then when you start adding heat it becomes less ridged and the inner, and outer drive shaft tubes begin to resonate and wobble at different frequencies....thus the major vibration.

So I had a new solid one piece drive shaft made, and have not had a problem since.

My gut has been saying driveshaft. Thanks, if my wheel balancing doesn't show anything this I think this will be what I will look into. I didn't know they where made that way. How can I tell if it is a 2 piece? Who made yours?

 

[thrashingcows]

My gut has been saying driveshaft. Thanks, if my wheel balancing doesn't show anything this I think this will be what I will look into. I didn't know they where made that way. How can I tell if it is a 2 piece? Who made yours?

It's pretty obvious if I recall. Near the rear of the drive shaft it will appear that there are two different size tubes., the main tube from the front to towards the rear is a larger diameter. And one looks like it's going into the other....which it is. ;)

I had a local drive line shop build my new drive shaft. Brought them in my old one, and told them it had to be identical. Had them swap over the transmission slip yoke, and new U-joints as well, since it all should be balanced together.

 

[rexus31]

I'm 95% certain the driveshaft on my '65 is once piece.

 

[Zymurgy]

Well what do you think? This is a blow up.

 

[65sporty]

One piece, but since it's out have it balanced

 

[Zymurgy]

One piece, but since it's out have it balanced

Thanks, actually it is back in now, but you can tell from the picture it was quite rust and I painted it before I re-installed.

 

[thrashingcows]

Sure looks like a one piece drive shaft. Does that balancer on the end have a rubber ring or anything? Sort of looks like a harmonic balancer....sure it's supposed to help dampen vibrations.

 

[Zymurgy]

Sure looks like a one piece drive shaft. Does that balancer on the end have a rubber ring or anything? Sort of looks like a harmonic balancer....sure it's supposed to help dampen vibrations.

No I didn't see any indication of a rubber ring on the exterior of the shaft. I took some of the surface rust off and painted it with POR 15 and didn't see anything but metal. It does seem like a harmonic balancer on the end, I remember it clean up pretty good not pitted like the shaft.

 

[rexus31]

Get it balanced Mike. It could have a slight warp to it. If so, have a new one made with the ends from your original. Any competent drive shaft shop should be able to do it.