I've never taken one apart, so can't offer any advice. If it were me, I'd be inclined to try a small amount of "percussive maintenance" to coax things apart.

I do appreciate seeing one of these (mostly) disassembled! I've got one in the parts bin, purchased out of curiosity. I'd wondered how the internals worked, and didn't consider that it might be a simple linkage rod that kept things parallel. That seems like it would be prone to wear,

Steve in Peoria