How do you remove the piston unit of pelikan 100nn

[lowks]

I tried to use the Twisbi vac 700 to fit into the piston thread but it doesn't seem to fit.

[Sevenof9]

the wrench only fits the M800 and M1000.....

[carlos.q]

There is a protocol for this type of situation:
1. If it ain't broke, don't fix it. A vintage 100n is not a TWSBI so don't remove the piston unless absolutely necessary.
2. Consider sending the pen to a repair person. It is sad to have a pen survive 60-70 years only to be destroyed by an inexperienced user.
3. If the above instructions do not apply, a visit to this page may help:
http://www.caprafico.com/pens-88/pelikan-pen-restoration-275

[Jeph]

The potential brittle threads ( and reverse threading) does make it non-trivial for removal. I use gentle heat and a thin leather strap to unscrew the piston housing. I have only destroyed a few that way. I have tried making a proper wrench but have not managed to end up with one that I find acceptable.