308QV Shimmy Problem

First off, I don't really know how to spell "shimmying," but I think you get the idea. My 1984 308QV has an intermittant shimmy when I get around 60-70 mph. I'm not real sure of the source and it does appear that it comes from both the back and the front of the vehicle. I say "the back" because I can hear the inside of the car creak with the shimmy and feel it somewhat in the seat. I say "the front" too, as I feel it also in the steering wheel. The steering wheel does not shimmy in a rotational sense, but rather horizontally--back and forth(at least it seems that way). Any list of suggestions here? Tires, shocks, brakes, steering rack, suspension, etc., etc. Let me know what you think.

Andrew

Andrew,
Starting with the easiest items to verify first...

How old are the tires?
Tire pressures?

Bring the car to a shop that can balance the tires...and verify the condition of the belts. Specifically, the shop should have a "road force" type balancer. This will detect if there are belt shifting issues with the tires.

If the above checks "OK", then the most likely culprits would be:

Wheel bearing looseness or suspension bushings...

I had exactly the problem you describe with a new car...and the problem turned out to be shifting belts in the tires...!

Regards,
David

Andrew,

I had the same thing in my QV. I took the wheels off and had Discount Tire balance them. The shake went away. Then I had a four wheel alignment done. That made an even bigger difference in how the car felt. Money well spent IMO.


JL

Answer to David: Well, the tires are starting to get to the lowest legal level. They could use replacing--granted. I'm just not wanting to lay down $ for new tires only to have the wear improperly due to a shock or suspension problem. Maybe belt separation is the problem, but I cannot see anything by inspection. If Discount tires can do a proper balance then that's a cheap "check." To check wheel bearing looseness is simply a matter of jacking up the wheel and putting torque on it while elevated, right?

To Jeremy: Alright, I'll take the tires to Discount. Who did your alignment?

Thanks all.

Andrew

Andrew,

West Pearland Tire and Auto did the alignment. Their equipment was brand new at the time (computer laser machine), and they gave me a computer printout of the before and after conditions. I am not kidding when I said that it made a huge difference. My car was way out of spec.

Where ever you go be sure to bring your owners manual in case they need the numbers.

As stated, start with a simple wheel balance--the weights come off all of the time. This is the typical symptom of an out-of balance wheel. Of course, other suspension issues could account for it too, but start here. By the way, I had new tires installed on my '85 this Spring and it took 3 trips to the tire store to finally get them balanced them properly--ie to get rid of the shimmy.

Nobody has mentioned the notorious outer bushings in the steering rack. This will set up a horizontal shimmy in the steering, especially in freeway ruts.

BTW for the last 50 years, a shimmy at 60 MPH is the (THE) classic tire imbalance symptom.

"Well, the tires are starting to get to the lowest legal level."

Do not waste money balancing old tires, especially tires that may have worn unround in the process of being imbalanced for some miles.

As others mentioned, have the bearings, bushings, and rod ends checked. As old as this car is, the bushings are likely on the way down hill. Do not align a suspension with rotting bushings, the alignment won't hold.

Follow up. Mitch Alsup and others were exactly right. Took it to the tire store for balancing. The tech said "Wow, it must be hard to keep your hands on the steering wheel, huh?" He said that both front tires were out of balance, but the right front was almost "intentionally" bad. Got the car out and presto--real Ferrari feel to it! Now I'm in love.

Andrew