Jedi Appliance Guy: Rusted on York condenser fan blade.
Jedi Appliance Guy: Polish the shaft above the blade with sand cloth.
Jedi Appliance Guy: Polish the shaft below the blade with sand cloth. Tear it into thin strips that will fit if you have to.
Jedi Appliance Guy: Polish the shaft and polish it some more. Don't stop till it's shiny.
Jedi Appliance Guy: If you haven't already, remove the set screw.
Jedi Appliance Guy: Spray it with good ole WD40
Jedi Appliance Guy: The oldest tool I own. It's not really a tool. It's a piece of 3/4 pipe.
Jedi Appliance Guy: Use the hammer and the pipe to push the blade down onto the polished shaft near the motor.
Jedi Appliance Guy: You can see where I'm going with this.
Jedi Appliance Guy: Polish the shaft some more, especially the newly exposed areas.
Jedi Appliance Guy: You can grip the shaft with an adjustable wrench and spin it while holding the blade still.
Jedi Appliance Guy: work the shaft back and forth while holding the blade. let the weight of the motor do the work for you.
Jedi Appliance Guy: Slides off like a stick of butter on a hot air conditioner on a Summer's day in Florida.
Jedi Appliance Guy: when replacing a York condenser fan motor and module, I use some silver tape to hold the module to the sheetmetal cover.