Some items from this specific schematic: Pin, Gasket,cylinder (mca), O Ring(d:2,id:70), O Ring(d:3.05).
The lowest price component in this Cylinder parts-list fiche is the Pin.
The Gs400e 1979 (n) (e01 E02 E04 E17 E18 E21 E22 E24 E25 E30 E34 E39 Cylinder consists of six pieces with the Cylinder being the most expensive.