I use this stuff for locks and clockwork indicators called "TRI-FLOW".
I know that Teflon oils seem to be all hype but the stuff actually
works better than any other oil I've used for locks. Doesn't gum up
the locks and penetrates well. Maybe it will also help with the static
friction problem you have. Stiction is a problem with some mechanical
measuring instruments I use in the machine shop because they get oil
on them and gum up. Clock oil doesn't work as well as Tri-Flow does
for these tools. I think it's because the solvent in the stuff allows
it to penetrate better and the residue left behind isn't very tacky.

Thanks for the suggestion. I'll look for it.

By the way, I neglected to mention that the ball-and-socket is plastic, with
a metal band in the socket.