I have removed prob more of them than most
first thing to do is get the left pedal shaft out.
To do this remove the cotter pin in the shaft.
disconnect the brake clevis.
take a wire brush on a drill or what ever your powered brush is and polish the shaft between the brake pedal and the clutch pedal get all the paint and rust off.
take the locking set screw out .
then go to the left side of the tractor and use a large cresent wrench on the pedal rod arm and try to turn it if it turns GOOD let the pedal hang down so you can spray penetrant in the hole where the set screw was and turn it both ways add penetrant untill it turns freely .
If not use heat on the pedal where the shaft goes through.cool with penetrant it will draw it in like soldering. do this several times and try to turn it again with the wrench .
i have used a slide hammer to pull them from the left side i made a bracket for the slide hammer to attach to the rod.
Leave the right pedal alone till ya get the floor pan off and then you can put it in a vise and work with it.
Hope some of this helps.