The most reasonably priced component used on the Gs1000h 1980 (t) (e01 E02 E04 E17 E18 E21 E22 E24 E34) Rear Calipers is the Bolt.
A sample from the products for the Rear Calipers include: Boot,piston, Piston Set, Spring, Cap,breather.
The fifteen Gs1000h 1980 (t) (e01 E02 E04 E17 E18 E21 E22 E24 E34) Rear Calipers component parts are all listed in this schematic.