I think a better solution is to cap the whole top so water doesn't get in at all. I found that a plastic, clear SOLO container from my grocery store measures 1 3/4" deep by 4 5/8" diameter (I think it was on the olive bar for takeout). You can wiggle this in and place it over the everything so water does not get in at all. I will play with this because you need a way to secure it so it does not flop around - maybe silicon adhesive?
I plan to dry it out, paint the bolt with Rustoleum, then secure the cap over it.