Piston for hydraulic pumps having .98 valve chamber blocks for models MF135, 150, 165, 175, 180, 1080, 1085, 20 IND., TURF, 230, 235, 240, 240P, 245, 250, 265, 270, 275, 275, 285, 290, 298, 360, 362, 365, 375, 383, 390, 390T, 393, 396, 398, 399, 670, 690, 698, 699 HIGH FLOW PUMP - INTERMEDIATE PUMP Using .98 diameter piston rings part number 897493M1 .