The lowest price component in this Rear Brake Master Cylinder parts-list fiche is the Screw,flat,4x40.
In this schematic the "Washer,oil Bolt" is used most often.
Some items from this specific schematic: Hose B,rear Brake, O Ring,14.8x2.4, Washer,oil Bolt, Circlip,rr.m/c.