Parts such as the Oil Pump: Washer, Plate (1e7), Ball, Oil Pump Assy, Hose (l200) are included in the Ag100h 1996 3ha9 Oceania 263ha-700e1 Oil Pump parts fiche.
The lowest price component in this Oil Pump parts-list fiche is the Ball.
In this schematic the "Screw, Pan Head" is used most often.