I have a 1985 Merc 1150 in-line six. The twin power trim pistons have
(actually, had) a freely-rotating ball bearing at the tip where it
contacts the engine body. One has corroded and disappeared completely,
and the other is close to doing the same thing. Is this an item that
can (or needs to) be replaced, or can I live without it and not do
damage? I'm hoping that if it should be fixed it wouldn't involve
replacing the entire piston assembly. Any thoughts?

Thanks in advance for any replies.

Rick