Parts such as the Front Master Cylinder: Boot,dust, Nut,6mm, Holder-brake,master C, Cylinder-assy-master are included in the Z305a3 Csr 1988 Europe Front Master Cylinder parts fiche.
The twenty-one Z305a3 Csr 1988 Europe Front Master Cylinder component parts are all listed in this schematic.
On this parts fiche the Washer,10.5x15x1.5 is the most specified component.
