FS40c curved shaft

Having a problem with my favorite little weed eater. It broke string off and I could not unscrew nut. Finally took channel locks to get to bolt only to find it could not be unscrewed because the whole shaft turned. I took the advice from another member and took a hacksaw and made a straight head screw head on the end of the shaft. Bolt came off but I am not convinced the problem is corrected. There was a c-clamp that I have never seen loose inside the head. I thought I would replace the end bearing assembly but have not figured out how to remove it. Any advice would be helpful at this point, thanks in advance.