[1967Tempest]

Did it with the TH350 now doing it with the 4 speed. Get her up so speed and she shakes in the floor and seat.

Does it in neutral and with the engine off.

All new bushings every where. New driveshaft with new u-joints balanced etc.. Had tires balanced a few times no dice.

I did have a previous shake that the 180* swap on the shaft did work. This is different.

I thought motor mounts, but it does it in neutral at an 850 idle on the highway. Not in the driveway revving it.

New front Bilstein shocks. All new front end components.

I had one idea that the spring might not be sitting in the "CUP" of the lower control arm, but not sure how that would effect it.

Any ideas????

[wrenchmen]

Are the tires wearing flat and smooth?

sounds like you have eliminated the drivetrain with your testing...but maybe one
of your rear axles has a little hop in it?

[1967Tempest]

Originally Posted by wrenchmen

Are the tires wearing flat and smooth?

sounds like you have eliminated the drivetrain with your testing...but maybe one
of your rear axles has a little hop in it?

They are original....... That would make a vib??

[wrenchmen]

I have seen tires that wear unevenly across the surface {usually rear tires on a truck}
cause a "hop" feeling.

Inspect your tires real good, look for any irregularities/bulging of the sidewalls.

If one of your rear axles was bent, yes it could cause a vibration.

[1967Tempest]

Will do. Tires were new last season. Could I get flat spots from sitting in the winter and never known all this time???

[wrenchmen]

If the tires are new and have not been damaged, like ran into a curb or something Its unlikely they are the problem...can you remember if you had the vibration before you replaced the tires?

A bent rim could cause a problem also...do you have another set of tires and rims you could put on to eliminate yours as the problem?

You can check the rear axles with a dial indicator, or you could just jack up the rear
so the tires are off the ground, lie something under them like a socket as a reference...about a 1/4" away and spin the tire, watch the space between the tire and socket for variation.

While you have the rear wheels off the ground, spin the and try and feel for any roughness, movement of the axle bearing....also check your front wheel bearings.

Just thought of something else...check that your lug nuts are properly seating in the taper of your wheels, wrong nuts or worn rims can cause the lug nut to tighten, but not firmly hold the wheel in place correctly.

[PontGuy]

My car shook when I bought it and new tires, suspension bushings, etc. did not help. I had a shop mount the wheels on a balancer and check runout on the rims- sure enough two were bent. I couldn't tell just by looking at them, but a new set of good wheels solved my problem.

Walt

[Samhatco]

Could possibly be axle bearings or pinion bearing. Do you have any play in the driveshaft? Could also be pinion angle. Just something to think about.

Sam

[1967Tempest]

no play in driveshaft on rear end. The axles might be a cause. I did notice that one front tire was a tad low on air today.

I put 50 miles on her on Sunday. SHe runs great and pulls HARD. Shame it has a vib..

I am going to a cruise on the 8th of May to a garage. might ask him to take a look. He is a big Pontiac guy.

Thanks\Dave

[Samhatco]

Originally Posted by 1967Tempest

no play in driveshaft on rear end. The axles might be a cause. I did notice that one front tire was a tad low on air today.

I put 50 miles on her on Sunday. SHe runs great and pulls HARD. Shame it has a vib..

I am going to a cruise on the 8th of May to a garage. might ask him to take a look. He is a big Pontiac guy.

Thanks\Dave

Do you think it may be an out of balanced drive shaft or bad u-joint? You might want to have it checked. Its not that big of deal to pull the shaft and take it to a shop to check it, if one is nearby. I had the same problem on an 84 CJ7 and found that the shaft needed balancing.

Sam

[1967Tempest]

Originally Posted by Samhatco

Do you think it may be an out of balanced drive shaft or bad u-joint? You might want to have it checked. Its not that big of deal to pull the shaft and take it to a shop to check it, if one is nearby. I had the same problem on an 84 CJ7 and found that the shaft needed balancing.

Sam

I brought the original driveshaft to be balanced. The guy showed me a 8" dent down the shaft. He made me a Heavy duty shaft and added new U-joints and balanced it etc... I thought that was gonna cure the problem..

Darn.....

BODY BUSHING??????? I'm sure mine are rotten..

[Samhatco]

Originally Posted by 1967Tempest

I brought the original driveshaft to be balanced. The guy showed me a 8" dent down the shaft. He made me a Heavy duty shaft and added new U-joints and balanced it etc... I thought that was gonna cure the problem..

Darn.....

BODY BUSHING??????? I'm sure mine are rotten..

Well... if the previous owner put an 8" dent in the drive shaft, that could have somehow bent an axle or affected the bearings in the carrier. Have you put the car up on jacks and run the car? Maybe you could see how the drive train is working... possibly be able to see if the rear wheels are vibrating. Just an idea.

Sam

[1967Tempest]

Originally Posted by Samhatco

Well... if the previous owner put an 8" dent in the drive shaft, that could have somehow bent an axle or affected the bearings in the carrier. Have you put the car up on jacks and run the car? Maybe you could see how the drive train is working... possibly be able to see if the rear wheels are vibrating. Just an idea.

Sam

Thats next on the list.

Thanks!!

[1967Tempest]

UPDATE!!!

I was looking for loose front end stuff......

WOW.... The driver side sway bar bushing is toast. The screw that holds it in must have finally stripped out. the bracket is completely bent outward. the bushing is closer to the passenger side!!

WOW..

Gotta fix that!!!!

[1967Tempest]

I fixed above.

Other than the axles can I get a list of things that might cause this?? I was on the highway again today. Noticeable at 65ìsh. More noticeable at 80-85.
Thanks
Dave

[David Jones]

You said the tires had been balanced? Was that on one of the computerized machines that can tell you if you have a bad wheel, a bad tire or if your children have blue eyes? The local Ford store down the street from here has one and it pin pointed a bad wheel for me once.

[1967Tempest]

Originally Posted by David Jones

You said the tires had been balanced? Was that on one of the computerized machines that can tell you if you have a bad wheel, a bad tire or if your children have blue eyes? The local Ford store down the street from here has one and it pin pointed a bad wheel for me once.

HAHAHA..

The fronts I had done on a machine like that. The rears at the local shell station. SHould I have the rears done again???

[1967Tempest]

Oh, this might help. As I was on the highway I noticed a difference than be fore. Probably, cause I was actually paying attention.

1 would be the vibe 2 would be the fluctuation vibe

(no pattern below just adding pieces to the puzzle)
11111111112222111111111111222211111111111122211111 112222111111

Again speed related, not engine related. did this in neutral today.

[Samhatco]

I thinks the next logical step would concentrate on the axles and carrier/pinion bearings as your culprit. You have just about eliminated everything else.

Sam

[Bill Eveland]

Is this a pulsating vibration at speed or just vibration all the time at speed. Usually any flat spots from tires from sitting should work out with 15 minutes of driving. Try rotating the tires if they are the same size to notice any changes. Or better yet try someone elses tires and wheels. Test drive their car before you swap to know they don't vibrate like yours. If it does come back to the driveshaft, if it was balanced correctly a cure would be to add more weight to the driveshaft , added weight changes the point of resonance.

If you had to get access to a sirometer (used to tune 1 cyl engines, briggs and stratton tool) you could measure the frequency of the vibration. A local small engine repair shop may loan it out. They only cost about $20. Have someone else drive the car to the vibration speed, put the sirometer against the floor or seat frame or something solid. It has a wire that uncoils and at the point of resonance the wire will shake hard. Read the graph that shows rpm, frequency in HZ. That will determine between driveline and wheel speed what the problem is. I would start with swapping tires first though.