For my blue 1979 Cutlass Calais I am experiencing noticeable vibration in the front end between 55 and 65 mph then it smooths out & goes away. Also, it's inconsistent, sometime it does it, sometimes not. I tolerated it and didn't think it was really bad, but now my wife has noticed it so now it's really bad.

My current drivetrain is 260 motor, 200R4 trans, 3:08 posi rear in this car. I'm running about 1900 rpms at 65 mph in 4th. But it makes no difference if I'm in 3rd (about 3100 rpms at 65 and man, this car hates that) or 4th with the front end vibrations, still occurs.

I'll probably try swapping front wheels for back to see if that helps. If that doesn't work I guess I'll pull all of them and have them all broken down and re-balanced.


The tires are the American Classic P205-75R-14's, are about 4 years old & have no more than 2500 miles on them.


This is on my to do list as I'll be taking this car to the 2016 Nats in Tennessee.


Other than what I plan on doing, would anyone have any other tips on what I should be looking for to get the ride back to smooth? The front end is for the most part rebuilt but I will say I did not get a new alignment when I got the new tires mounted.


Thx,

 

I would start with checking the tire balance and looking for flat spots.

 

A dead front shock can cause them to do that too.

 

I think if this were the case it would just get worse the faster you go.

I have seen tires bouncing like a superball on steroids in the wheel well on the freeway and it never ceases to amaze me how people can go down the road like that like nothing is wrong while the car vibrates apart around them.

 

sticky brake caliper can cause a vibration thats not always present and only manifests itself at higher speeds when present.

i would rnr caliper slides and brake shoe slides if caliper is really grimy piston may have some deposits that can be cleaned as well.

 

Does the vibration go away after it is driven say 10 miles on the highway ,after the tires have had time to "warm up".If my car sits (in the basement on concrete for long periods of time ) I've noticed some vibration for a short time but it goes away after a few miles.Mine seems to be mostly in the front,but the engine/ transmission weight would attribute to that.When I know mine is going to sit for long spells,I park it on four pads of indoor /outdoor carpet and it seems to help greatly. Larry

 

Before demounting the tires, mark the wheels and tires, and remount the tires to the wheels with the marks 180 degrees apart.

 

Thanks all, I'm going to try out swapping the fronts for the backs & see how that goes. Not confident but it's worth a try. I'll move on to the next step if that doesn't work.