The brake pedal in my '55 2nd 1/2 ton is connected to a shaft that goes through a hole in the floor. It connects to an "arm" that hinges on the master cylinder.

I'm trying to get those 2 parts disassembled (pedal shaft and arm). There's a castle nut holding the brake pedal shaft to the arm, but the 2 parts are stuck together pretty solidly.

Do those parts thread together or is it a press fit? Would a small puller tool get them apart? Anyone done this?
LT