An improved magnetic drive pump is disclosed with improved bearing support for the proximal and distal ends of the rotor shaft. Further, an improved mechanism to couple the inner magnet assembly to the rotor shaft is also disclosed. Finally a mechanism for sealing the pump chamber from the interior of the canister that surrounds the inner magnet assembly is disclosed which permits a separate supply of coolant to be used for cooling the inner magnet assembly and the proximal end of the rotor shaft wherein such a coolant is not the fluid being pumped in the pump chamber. The pump chamber is isolated from the interior of the canister.