Pro Form Elliptical Cross Trainer uppper arms sliding on pivot axel!??

The top part of the left and right body arm were sliding back n forth along the pivot axel while in use.

In my attempts to fix this movement I removed the left and right upper body arms to remove the pivot axel and put it back together but the same thing happens as soon as you start using it, it slides back and forth on the pivot axel.

So in trying to fix it i seem to have made the problem worse as now the upper boday arms slide apart on the pivot axel when using it. As time has gone on this has become more frequent to the point where it is no longer useable as the left arm seems to slip and want to slide off the pivot axel.

What should hold the arms together so they do not slide apart and which parts would I need to repair this so this no longer happens?

Have I moved something or positioned something wrong as the right arm seems to be more stable than the left around the pivot axel

I was hoping for some advise.