I just took in a Lamy 99e via that 'Bay thing. A very nice pen, once the ink the thoughtful seller left in it was cleaned off, but I discovered a bit of a problem-- at a couple of points during the upward travel of the piston, some counter-pressure develops and drives a quantity of the fluid just taken in back out. This results in a half-load of ink as best.

What I think is happening, and would like comment on: The fit of the blind cap threads to their mates in the body is such that the dry space above the piston becomes sealed during the upstroke. As the piston rises, it pressurizes the dry space, and the pressure eventually blows past the piston seal and into the wet space, pushing out some ink. What I don't get is why a negative pressure doesn't form in the dry while working the piston downward, with a similar effect at some point pulling fluid up past the seal-- all I get from turning the knob with section submerged is a steady stream of bubbles.

I want to lubricate the piston, but I'd rather not have the pen slightly slimy if there's some other modification needed. The only thing I can think of is drilling a teeny hole in the top of the blind cap to allow for air to move freely in the dry space, and I really don't want to do that if anyone can suggest a less drastic remedy.

My impatience leads to results which I'll share: I took the pen even more completely apart and found a slight deformity in the piston seal. What I took for a reverse pressure was in fact a failure of the seal, and like a straw with no face on the top end of it, the fluid just fell out until the seal was re-established. So, some manipulation of the seal and a packing of its spaces with silicon grease, a surplus of grease laid on its upper surface (the dry side), and upon reconstruction everything appears to be working.

In the reservoir, at least. Now it appears that the feed is starving, which may be a result of the thing making an trans-Atlantic flight with a load of ink inside it. Well, inside at the beginning of the trip. It was all external when it got here.