Need some help..

Over the winter my son and I replaced the rear trailing arm bushing with Delrin replacements (left and right), however we did not replace the pivot shafts as they seemed to be ok. Everything seemed fine and come spring time we started driving the car on nice days and did 2 autoX events with our local PCA.

After the second autoX event my son told me the car was making a clunking sound at the right rear and when we looked you can see the bushing slipping on the pivot shafts. At first I thought the outer mounting point had moved allowing a small gap between the inner mounting point but that did not seem to be the case.

When we looked closer what I noticed is with the control arm assembled the pivot shaft is longer than the control arm with both bushings installed, so it seems impossible to "close" this gap that allows the bushing to slide left and right.

With this in mind what have I done incorrectly that is now causing this problem? Reading some other posts it almost seems like I need either a washer or some kind of shim and/or the need to use JB Weld.

Any help or feedback would be fantastic..

it has been too long since I had mine apart, but this is what I used from elephant racing. Not cheap, but rubber with tools and great service. They have a video on the installation.

Click to view attachment

The shafts have serrations on the ends so they don't rotate (I assume). But in the exploded view diag from AA, it does show a washer on one end. And I know the nuts are special. They should have a step on the inner edge. You can kinda see the step on the AA drawing. The mounting hole on the car and the ear are too big for the shaft to be tight, but the step on the nut makes up the difference, so the shaft will not move.

Do you have the 1 washer and the special nuts?

Click to view attachment

EDIT...
Found a photo of the special nut and the serrations:
Again, you can't see it very well here, but the nut has a fine slit going across a few flats that acts as a lock.
Click to view attachment

I have some shim washers for that purpose.

so should I have also replace the pivot shaft also and in that picture I can see the pivot shaft has the same issue with it being longer than the trailing arm and bushing.

I would say that is correct, so the serrations will grab.

now I understand... that is not my problem with the pivot shaft slipping or rotating but the bushing sliding to the left and right. In the picture above you can see when looking at the serrations you will notice the shaft is longer than the bushings. It is this gap that I am trying to understand how to deal with.