Soundguy,
You are correct, that the "standard" jinma 200 series hyd plumbing, has some issues. Most of it is with those disconnects that are right after the pump, designed for the ZL20 FEL hook-ups. Some importers/dealers, plumb Koyker or other US FELS past the diverter valve. I have not heard specific pump problems with those hook-ups, but don't know for sure.
I have been considering, for a few years now, revamping the standard Jinma hyd plumbing, especially with respect to the FEL hook-ups. What would be helpful to me, is detailed info on newer tractor hyd systems. Can you provide that info off of one of your tractors? The plumbing schematic, and any additional info, would be great. The more detail, the better.