68 proportioning brake valve

Has anyone rebuilt one ? is there a way to test it - working on the wago - redoing the lines and the p valve is just crusty - I see many replacements on line cheap enough - but am I better with original then new ? thanks

i don't consider those to be proportioning valves. they're just distribution blocks with a safety built in. i'd just take the one you have apart and see how cruddy it is inside first before i bought one. they're pretty simple. proportioning is built into the master cylinder .

Does the car have disc brakes? Does the plumbing look like this? If so:

https://www.classicindustries.com/product/1968/dodge/charger/parts/mp500503.html

no drum

Then, as stated above, there is no prop valve.

https://www.classicindustries.com/product/1968/dodge/charger/parts/md2267.html

Just some o rings and plunger and spring. Easy to take apart if it is clogged. Kits with O-ring are available for get name of the company. They are Mustang people I believe.