Abstract: An interlocking device for rigidly holding together the body and flange of a hydraulic machine includes a body, flange, gears, sealing elements acting as a body seal and lobe seal adapted to effectively seal pressurized oil pockets within the hydraulic machine with a back-up ring that prevents squeezing of the lobe seal and to retain it in its original position, appropriately dimensioned bush bearings adapted to act as load bearing journals. The interlocking device includes a plurality of bean-shaped dowels located at both inlet and outlet sides that hold the body and flange together with minimum relative displacement to ensure high volumetric efficiency of the hydraulic machine even at high operating pressures in excess of 275 bar or higher.