Some items from this specific schematic: Arm B Comp,fr.brk, Pin,split2.0x12, Panel,fr Brk, Washer,14mm.
This FRONT BRAKE PANEL assembly utilises two Spring Brake Shoe(s) - the highest specified component.
The most reasonably priced component used on the Xr500r 1981 (b) Usa Front Brake Panel is the Nut,thin 6mm.