Leak from rear of lockdown vacumatic

[CVR]

I've got a lockdown vacumatic that fills nicely. However, I notice that if I fill the pen with water, hold it with the nib up, and pump the filler piston, water leaks out of the back (i.e., down the lockdown filler rod).

 

This must signify a damaged diaphragm, but then why is it filling so fully? It blows air bubbles nicely when the filler rod is depressed, and sucks in the water nicely too.

[Ron Z]

From the ever present, "This shouldn't be happening but it does" category in pen repair.  I have a tool that I made that is a duplicate of one that Parker sold to test a diaphragm.  It is a plastic piece with a place to put on a  rubber desoldring bulb on one end, and threaded inside on the other.  It screws onto the blind cap threads, tight against the end of the barrel.  Squeeze the bulb and it forces air into the barrel.  Immerse the nib in water and if there are any leaks, bubbles will show up in the water.  I suppose that you could just fit a bulb over the end of the barrel to get the same results. 

 

I just checked my files, and I don't have a picture.  I'll post a picture when I get a chance....