Abstract: Presented is a fluid drive motor that may be attached to a conventional garden hose, for instance, to effect reciprocating motion of a drive shaft that may be connected to a utilitarian device, such as a scrub brush. The fluid drive motor is provided with a piston assembly that responds to the pressure of the fluid to translate the piston assembly from one position to another and in so doing imposes rotational reciprocation on a drive shaft that extends out of the motor block of the fluid drive motor. The reciprocating characteristics of the piston assembly are controlled by the imposition of fluid pressure, and the imposition of fluid pressure is controlled by a valve assembly cooperating with a reciprocable magnetic bar to channel fluid under pressure alternately to opposite ends of the piston assembly.