Abstract: An improved hydraulic device includes a rotor which is circumscribed by a cam surface. A series of peripheral slots are formed in the rotor. Each of the slots receives a pumping element which is spring urged toward engagement with the cam surface as the rotor is rotated relative to the cam surface. Each rotor slot defines a spring receiving recess extending from one major side surface of the rotor to a location between the major side surfaces of the rotor. The recess allows axial movement of a portion of the spring in one axial direction and blocks axial movement of that portion of the spring in the other axial direction. Each pumping element preferably defines a spring receiving recess which allows axial movement of another portion of the spring in the opposite axial direction and blocks movement of the spring in the one axial direction. The spring recesses facilitate assembly of the hydraulic device and resist undesirable spring movements during operation of the device.