On this parts fiche the Spring,rr.brake is the most specified component.
This Rear Brake Panel diagram displays the required parts for the Vt750ca 2008 (8) Australia / Kmh St Rear Brake Panel.
The most reasonably priced component used on the Vt750ca 2008 (8) Australia / Kmh St Rear Brake Panel is the Pin Cotter 2.5mm.