Lately I have noticed that the thumb bar is very hard to press down to allow the spool to spin. It's still working, but there are times where I almost have to use both thumbs to push it down to get it to disengage. I take my reels apart and clean and grease/oil them each winter, so when I have it apart this winter, what should I look for or replace so that it's back to working like normal again? Thanks!