Since I got my C4S I've been trying to track down a rattle that I've been hearing from the right rear side. I was finally able to track it down. Turns out it was the wing that had just a tiny bit of play. Took it apart and put some tesa tape on the inside of the wing and the frame area. Tightened it back up and there's no longer any play. You have no idea how much that was bugging me!

 

There is no better sense of satisfaction, relief, and pleasure than banishing an annoying rattle. Cheers!