Thanks Jeph,
I took your advise and have been soaking the 400NN body in pen flush for several hours today.
There was no ink residue in the fluid, so the pen was clean.
Additional searching of web pages led to a nice description of how to remove the piston unit from the body (you have to push it through from the front to the back).
http://www.penboard.de/penpoint/en/f...PenRepairs.htm
I was able to remove the piston unit from the body, using the plastic top from a wood glue applicator that fit down the top of the pen. The piston unit, thanks to the long soak in the solution, eased out after a couple of quick, light hammer taps. I supported the pen's body with a knockout block I made from a small 1x2 piece of wood with a hole drilled in it to allow the piston mechanism to pass through.
There was a small piece from the end of the piston that had broken off, but it does not appear to interfere with the workings of the filling system.
I applied some silicone grease to the piston's rubber seal and the threads of the mechanism. After adjusting the threads and housing, to increase the piston's travel distance, I re-inserted the piston unit into the pen. Needless to say the silicone grease on the seal made the process of putting the piston back into the pen's body much easier.
With the piston now working correctly, I can turn to replacing the broken nib collar and restoring full functionality to my first vintage Pelikan. I like the idea of ordering a couple of M200 nibs from Richard, one to use for the 400NN repair, but have another to put in my M205 DUO, as an alternative to the BB nib that is in the pen now. I have been interested in a Binderized nib and this is the perfect opportunity to get one.
I have uploaded a couple of photos showing the 400NN disassembled and a close up of the piston mechanism, and the nib unit parts (broken nib collar and all).
Thanks very much again to Jeph and Tandaina for your advise.
400NN disassembled.jpg400NN nib feed collar.jpg400NN piston disassembled.jpg
Bookmarks