Thrust washers Standard size for crankshaft in Perkins motors 3.152 and 4.203 this includes one upper and one lower washer for some of the following models MF35, 50, 135, 150, 165, 2135, 230, 235, 240, 240P, 245, 250, 255 with ad4.203 motor, 3165, 360 T3.152.4 Engine, Replaces (735112M1 upper without tab & lower with tab 735113M1), (Perkins number 31137211 upper without tab & lower with tab 31137212