Free counter weight
I did exactly what the previous poster said. You may have to take out the screws on top which hold the pully to get in there to spray. I used WD40.
BTW, I found I was alwasys getting water dripping down there from the mast,which cased the rust. I sealed under the mast, above the compression post with some expandable foam, and put small holes outside, on deck at the base of the mast to let any water out. Has worked for 6 years now. Oh, I also did something at the base of the compression post to drain, but can't remember at the moment what that was.