trevtherev

As Ive been roped in to help a friend get his car back on the road, I'm struggling to figure how to reassemble the filler cap. This has been in parts for about 6 months, and he has forgotten how it goes together. What I thought would be straightforward is somewhat stumping me. I can't seem to find where this thin ring goes (pic 3/4) I thought maybe it sits inside, and the centre key piece snaps down inside. Even out of the unit, the thin ring will not slide over the body of the centrepiece, and it all seems too tight. All the articles I've found so far seem not to mention this part at all.