I'm rebuilding my whole mechanical assembly and have a question about the spring in the main crank. What's it for and how does it work? I can't figure out if it's in torsion or compression. It's just laying between the sheet metal part the looks like the millennium falcon and a flat washer. It  looks like there's a hooked end that's worn off that maybe fits in the slot. Anyone know? I have a spare one and it's the same except for a plastic ring around the spring.