A friends door has a loud click when opening and closing the door that sounds like it comes from the lower hinge. I'm thinking this piece is turning rather than doing it's job. I would offer to work on it, but it would require emptying the door, then taking the door off the hinges and only then being sure as to what part to order. PITA It probably doesn't even bother her. I wonder if it will end up breaking something else if not fixed.
Why do you say the bottom hinge? Wouldn't it need to be on both hinges so the entire door will raise or lower?