[Brads65]

I have a vibration (bounce) in the car between 55 and 65 mph. My entire front suspension is new and I have new rear springs and shocks. When the car reaches around 55 mph the rear hubs appear to be bouncing up and down on both sides of the car while the front hubs seem nice and smooth. I viewed this while driving along side of the car with someone else driving it. When driving the car it actually feels like it's in the front and the front fenders bounce up and down but after viewing the hubs, I think it's in the rear end or drive shaft. I also have new universal joints in the car and the rear-end has new seals & bearings. It is not the tires or wheets, I've had 2 new sets of tires on it (presently Coker Dual Red Lines) and the wheels have been checked and rotated. I haven't changed the drive shaft but at 60 mph I put the car in neutral and the bounce didn't go away. Has anyone else had this kind of problem or know what it could be. Right now, I have a beautiful black, newly restored $40,000 65 convertible that vibrates or bounces!!

[preflight99]

Has the car been sitting for a while? Even though the tires are "new." If they have been sitting for some time they can develop flat spots, or be out of round.

[Brads65]

No, it hasn't been sitting. I've had flat spotted tires before and that isn't the problem with this one. Thanks for the reply though.

[preflight99]

Sure, didn't mean to insult you with such a simple answer. Sometimes it is the simple answer that cures the problem. Could be a rear brake issue that unknowingly locks up a rear tire on occasion causing a flat spot. There is an interesting post a couple spots down from this one, where the member mentions wheel hop caused by lowering the rear springs. Check it out, Lowering Rear End without reverse eye spring or lowering bloc . Good luck