Many types of blower fans for dryers have a plastic blower fan which has a metal spindle in the center which goes on the motor drive shaft. If the fan does not come off easily with moderate force – forget it. You will need to destroy the fan (crack the plastic) and replace the entire blower fan assembly. The fan has a plastic nut and will only handle moderate pressure until it will strip. In addition, the spindle will become fused to the motor shaft and will be virtually impossible to remove.