[beamrider42]

The first thing you need to do is get the threaded pivoting post out of the armrest. Look for a plastic tab where the post goes into the armrest. I think this tab pushes in against another springy metal clip that sits in a groove on the pivoting post. My pivoting post was stuck very tightly into the armrest, so tightly that I thought it wasn't meant to come out. Also, I made the mistake of trying to pull the plastic clip out, and it broke.

If the post wont turn easily in the armrest, try an appropriate lubricant, then while pushing in on the plastic tab, pull the post out of the armrest. Once the post is out, the rest was easy. Use threadlock and an allen wrench to screw the pivoting post back into the seat frame, the constant up/down motion and the stiffness is what I believe caused it fall off in the first place, it backed itself out. Then push the armrest onto the post until the metal clip re-engages the groove.

Hope this helps