In this schematic the "Washer,oil Bolt" is used most often.
Parts such as the Rear Brake Master Cylinder: Hose,rr.brake, Hose,rr.brake, Cap,oil Cup, Washer,7x12 are included in the Cb750f 750 Super Sport 1979 (z) Usa Rear Brake Master Cylinder parts fiche.
The Rear Brake Master Cylinder assembly is constructed from several parts from which the Cylinder,rr.mas. is the most expensive.