Pelikan 100N repair

[tandaina]

Well I got a beater 100N, flea market style. $20 for the pen and the nib is there. But wow this thing is pretty rough.

The nib and feed are loose from the collar which seem to still be in the section. (Were these friction fit rather than screw fit? How the heck do I get it out and all reassembled?)

The filler knob seem to have come loose from the filling/piston system itself. I can screw the filler out of the back of the pen but after that I've got no idea where to start.

So my chief questions:
1. Should I attempt this repair? The binde is in lovely shape, though the ink window and section are very cloudy, maybe just from ancient ink, I can't tell.
2. If Yes to 1 how do I get the nib/feed reassembled properly?
3. How to reattach the knob to the filling system properly?

Will post pics of the grissly patient when I get home. The nib seems SUPER flexi testing it on my finger nail so I'm excited about what this pen COULD be.