Civic proportioning valve leak on 3rd PV

[big_tiger]

Im wondering if anyone has come across this. The 93 Civic Hatch has a rear disc swap, Integra MC, and stock front brakes. For some reason the proportioning keeps breaking. Its weird because I swear I can't feel it break and start leaking. The pedal feels very stiff, and suddenly release and feel normal. I check the PV the next day and there is freaking fluid. Of course bled the brakes. No one makes a replacement anymore, and if they have one they are $150+.

Internet searching has come up with nothing, so I am asking here and on honda-tech.