RD won't move
A 80's Suntour RD doesn't seem to budge at all anymore (after riding through salty winter). The cable tension on the friction shifter seems fine, but it just won't move.
Is it possible some key part flew off? Should I oil the crap out of it, and press hard somewhere?
Without looking at the derailleur it would be impossible to find a "key" part that flew off.
To do this right you should remove the derailleur and clean with a water based water soluble degreaser and dry completly; next apply a dry lubricant like Finish Line Teflon Plus to the moving parts and pulleys. Then you need to oil the cable where it enters the housing.
Can you take off the rear wheel and see if you can move the RD with your fingers? You might want to lube the pivot points and exercise the RD with your fingers by pushing on the body.
Originally Posted by godspiral