I have a 5 gal. aluminum twin stack compressor. The motor burned out. I have the motor/stator/pump assembly removed from the compressor as a unit. Do I have to replace the whole thing or can I use the old pump assembly and a new motor? I can't figure out how the motor/stator come apart from the pump. I've removed the 4 long screws attaching the motor to the pump housing and it's still in there tight. Do I have to go in from the piston/cylinder and disconnect something? Any help with part names/numbers and dismantling advice would be great. By the way I know I can probably buy a new one for a little more than what the new motor might cost but I don't like throwing things away if I don't have to.