The Bolt 306258330000 is the most widely applied product in the RD400 1978 USA REAR DISC BRAKE - CALIPER ( eight times ).
The component with the lowest price in the REAR DISC BRAKE - CALIPER schematic is the Nut(661).
Parts such as the Rear Disc Brake - Caliper: Washer Lock 306258340000, Bolt 306258330000, Bolt, Bridge (1), Bolt are included in the Rd400 1978 Usa Rear Disc Brake - Caliper parts fiche.