I had to replace the ball rod assembly on a bathroom sink's pop-up drain since the old rod had corroded badly. I used a universal replacement kit that came with balls of several sizes and one very flimsy washer to seal the interface between the ball and the tightening nut. While trying to tighten the nut down for the first time, I cracked the washer, possibly by over tightening the nut.
Now I have a ball rod assembly that leaks around the ball. What is an appropriate way to seal that interface? The first idea that I had was to try a rubber O ring as a gasket. A #10 ring seems to fit well inside the nut, but it doesn't stay in place well when I tighten it (it tends to wrap itself around the ball somewhat, not staying in the joint between the ball and nut). It seems like some sort of rubber gasket would be the most sturdy solution, but I'm a bit out of my element.
Sorry if I mangled any terminology above; plumbing is definitely not my day job!