Abstract: A fluid pressure energy translating device comprising a housing defining a cavity and a drive shaft having a portion thereof rotatably mounted in the housing and extending into the cavity. The cavity has an open end remote from the drive shaft and a valve block closes the open end of the housing. A removable rotating group cartridge is positioned in the cavity between the valve block and drivingly engaged with the shaft. The cartridge comprises a valve plate engaging the valve block and an angle block, a rotatable cylinder barrel interposed between said valve plate and said angle block in abutment with the valve plate and in driving relation with the drive shaft. The cylinder barrel has a plurality of piston cylinders, each of which has a port for communicating the cylinders with a face of the valve plate, a piston in each cylinder, shoes connected to the pistons and engaging an inclined surface on the angle block. The valve plate and angle block are interconnected to form a removable cartridge.