Finally getting the top down on my 70 CS and noticing a slight shimmy during certain driving conditions. I've had the car since November and only notice it with the top down. I've had other vintage convertibles and notice a difference with the top down, maybe because this is a big car it's more pronounced. Or maybe I just need to get used to it. Meanwhile, any ideas?

 

Have your tires checked anyway. With the Top down all out side things are enhanced, noise. vibration,smells(good and bad) conversions of the guy in the car next to you. Can't imagine the top down taking away enough structural strength that would cause shimmy... Tedd

 

Nice car! I didnt think it would either, but I put the top back up for a day and compared. Definite difference. First thing I did was check the tires, they were off by about a # but not anymore. There's brand new shocks on there too. Im thinking an alignment might be in order. Im ultra sensitive to every noise, rattle, feel, etc. and the car is still relatively new to me, so maybe Im over-reacting. But I was wondering if anyone added any struts in the engine bay or anything like that.

 

Open your doors and look for a brass bumper and silver bumper ( one on door and one in jam) that contact each other when door is closed to stiffen body. If not there let us know.

 

Yes, in fact both the silver and brass plates are there. What's the story behind those?

 

They just help keep down the door to quarter panel flexing the way I understand it.

 

With the top down,
open the door and lift on the door (grab the door not just the handle) and see if there is play or does the car lift with the door. Do both sides one at a time. If there is play, your hinges may be worn. That may allow a little shimmy.

 

Almost sounds like cowl shake. But I wouldn't guess a car with a full frame would have that. I had an 03 Mustang that had cowl shake bad when the top was down.

Not sure how you'd fix that, stiffen the frame somehow or maybe there's some structure missing from the body.

 

1 check the door hinges
2 look at the rubber body mounts just to rule them out.
3 look at the gaps around the doors and hood.
4 Make sure the rubber bumpers and weatherstrip are present.
5 poke around on the frame looking for soft spots or rot through.
6 report your findings

 

Ive done some research myself and learned that these A-bodies do have some flex to them with the top down and the purpose of those shims. I had a '69 Corvair convertible and the dash rocked when a cross-wind came through. I'll double-check the doors on the Cutlass, though...

 

They do flex. I jacked mine up once with a floor jack behind the front wheel and the sounds it made worried me enough to start a thread about it. After that I always jacked it up from the center frame under the motor. I don't like loud popping noises.