Had a four wheel alignment job done (to the specs) to my -98 coupe some weeks ago. A week or two later I could feel that something was wrong with the alignment.

The same shop tried to set it up again, but this time they did not manage to set the Caster within the specs at the right side.

What can be wrong?

 

You may need to change a shim in the top control arm so you can adjust the lower control arm to get the proper castor.

 

Stock specs or your own?

 

Could you please tell me more exact where this shim should be installed, and where can I get these shims? Is it possible to get a drawing of how and where this shim should go?
Thanks

 

Stock specs.

 

There are two bolts that hold the top control arm to the frame. The shims are on the bolts behind the control arm member that bolts solid to the frame. The shim is just a washer that you can get from a hardware store. The factory washers on the bolts have a rubber center in them, but that's just to keep the washers from falling off the bolts while moving on the assembly line, until the bolts are put in the frame holes. It's been quite a while, but I think I had one shim on one bolt and two shims on the other bolt from thr factory. If you need more caster, then you will need to move the top ball joint toward the rear of the car which means taking a shim off the rear bolt or adding a shim to the front bolt. Which to do is dependent on the current lower control arm position for camber. If the lower control arm is in the back half of the adjustment slots currently, then it can come out away from the frame and adding a shim to the front top bolt would be the thing to do, which would also move the top ball joint out away from the frame and to the rear. Do just the opposite if the lower arm is in the outer half of the adjustment slots..