Our folding attic stairs worked perfectly for a while, then developed a problem. When pulled down, it's as if the spring has too much tension on it, so the bottom section does not rest on the floor. The spring seems to be in the proper place, resting on the top of the spring carrier. They are not cut too short, and we can "get around" the problem by hanging a bucket of water on the stairs to weigh it down. But of course we'd like to solve the problem permanently. Any ideas about what may have happened?