Parts such as the Oil Pump: Oil Pump Assy, Bolt, Clip, Circlip (22k) are included in the Dt50rsm 2005 2c37 Austria 1d2c2-300g4 Oil Pump parts fiche.
In this schematic the "Clip" is used most often.
The Dt50rsm 2005 2c37 Austria 1d2c2-300g4 Oil Pump consists of twenty-four pieces with the Oil Pump Assy being the most expensive.