This schematic depicts all components used in the Gl1500a Goldwing Aspencade 1997 (v) European Direct Sales / Kph Rear Brake Master Cylinder partslist.
On this parts fiche the Washer,oil Bolt is the most specified component.
The most reasonably priced component used on the Gl1500a Goldwing Aspencade 1997 (v) European Direct Sales / Kph Rear Brake Master Cylinder is the Screw-washer 4x14.