I had exactly same problem. There is no parts available-it has to be replaced as an assembly, that is why everybody is talking about winding and unwinding. The 1/8 pin is what is holding the big spring locked when removing from vertical rail. When out of vertical rail, remove tension with large crescent wrench and remove the pin before drilling the rivets out. New assembly will have to be wound-up after riveting into the drum and locked with pin before you can put in into the vertical rail. That is exactly what I did and still have all my fingers.