I got this Parker 51 in a while ago that had the squeeze unit all mucked up. It looked like someone had taken a pair of pliers to it to squeeze it. The feeder tube was almost all gone as well.
Howard at Bexley had done a new unit for these so you could use a cart. or a converter.
I set this one up to use a converter that is sealed into the pen.
The fit was not as tight as I would have wanted it so I used a bit on a clear sack that I cemented onto the section and onto the converter. I have use this as a daily use pen for over a week now with no problem at all.
All set to go