Severe front suspension vibration with column shake too

Well, first, I had the front wheels and tires spin balanced. I have 4 kyb shocks installed in the car, about 2 years old, the tires are 14 inch BF Goodrich radials ( 6 yrs old, but brand new ), This didn't help the shake. When traveling in town, sometimes the vibration comes on as low as 45 mph. Is thier a possiblity the lower conrol arms ball joints are worn causing the shake and vibration? I have noticed a wear mark on the right disc brake splash shield. It looks like the rub marks lines up with the shape of the rt lower control arm ball joint. The suspension is original except for the outer tie rods and strut rods which were replaced with new parts 2 years ago. Any suggestions??

I had a similar problem. Turned out my driveshaft needed rebalancing. Sounds like yours might have more to do with the steering linkage if it has wear though.

I had a similar problem. Turned out my driveshaft needed rebalancing. Sounds like yours might have more to do with the steering linkage if it has wear though.

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I'll inspect the driveshaft too. thanks.

If you don't know how to inspect them. Get your ball joints inspected. Soon!. Ball joints are considered a catistraufic failure.

If everything is original except tie rod ends, check the idler arm and pitman arm. It would be wise to get any "wear item" replaced. Ball joints, idler and pitman arms, tie rod ends, etc. These parts are 40+ years old and may have had dubious maintenance.

You have a tire balance problem. find someone that can spin balance on the car.

My 73 convertible has the same Violent vibration between 45 - 55 mph. When I say Violent, I mean the steering column shakes left to right and you can see the windshield pillars doing the same! Its worse on turns which leads me to believe that it would be suspension related but the front end is tight, alignment is on and it's had the same issue with 2 different sets of tires. It has factory steel wheels, KYB shocks and Firestone whitewall radials.

In the late '90's I was service manager for a Pontiac dealership. I had a customer with a Firebird convertible that had the same condition. After wasting a ton of warranty dollars on tires, struts, bushings, driveshaft, etc., a field engineer visited and test drove the car. He gave me a part number for front coil springs and explained that eliminating the roof from any car will compromise it's structural integrity significantly and that if the foundation (springs) are not strong a "mean rpm frequency" will develop causing vibration where the many rotating masses in the vehicle come into harmony - causing vibration.

This week I replaced the front coil springs and the shaking is diminished but still there. Any other ideas??

One more clue - I met my car's sister at the St Augustine, FL MCA Show back in April. I asked the owner if he had any vibration around 45-55 and he said "shakes like hell - that's why I never drive below 60!"

So is this common to 71-73 convertibles?

Anyone else having this issue?