Started restoring the resto-ride seat for my new to me 960. and have a question. The flip over bracket that attaches to the seat pan has a threaded stop on the front of the bracket. I assume this is threaded so it can be adjusted for seat height? Correct? Mine is stuck and have not been able to free it yet. Tried torch heat and no luck. Will soak in something next. But the main question is that there was a spring around the threaded part. (See attached pic) Does anyone know the purpose of this spring? Also did the seat pan rest on top of the stop, metal on metal or was there a rubber bumper of sorts?