Proportioning Valve Keeps Tripping?

[MikeB]

Originally Posted by KyleSeal

UPDATE 4/18

So, next I will install block off fittings on the master to see if I can have any pedal when flow is 100% sealed.

Yes, that should eliminate the master cylinder.

Also, I think the problem is something other than pedal ratio or master cyl bore size. As an example, when I installed 85 C10 spindles and disc brakes on my 69, I actually drove the truck for at least several weeks with its stock manual drum/drum master cylinder, and the brakes worked pretty well. Sometimes I wonder why I went ahead and installed the 71-72 master cylinder, booster, brackets, and pedal linkage! However, the system has worked great since then, minus some issues with the 50+ year old combo valve, and brain fade on my part when bleeding brakes recently.