A method for assembling a motor shaft with a bearing, a motor housing, and an impeller is disclosed. A motor shaft extension is used to retain the impeller axially on the motor shaft and allows the motor shaft to drive an additional component, such as an impeller, located a distance from the motor. The motor shaft extension may be fabricated from aluminum or hardened steel. Additionally, the motor shaft extension may be embodied in a tube extending past the end of the motor shaft and a shaft extension pressed into the end of the tube.