The ball studs on my level sensor were seized in the cups. I managed to get them moving and eventually popped them out but the ***** are heavily corroded. They seem like a simple thing to replace, but I can't find the official size of the ball stud. What's left them calipers at about 10mm, does anyone know the actual size?

Also, I'm tempted to just brush these with Ospho and then dip them in POR 15 and reinstall them, is that a bad idea?