Good morning Grigg.
http://www.jalopyjournal.com/forum/threa...kes-wtf.646567/That article covers both residual pressure valves and proportioning valves. I've been researching everything I can find on this subject for the past few days. What I've found is just like the article, a bunch of contradictory information. For example, some assert that even with a drum/drum tandem MC system a RPV is essential in each circuit. Others say no.
This research does indicate that the RPV is to prevent drain-back to the MC if the MC is below the wheel cylinders. On my stock '36 Chevy PU the MC is above the wheel cylinders.
The symptom of drain-back supposedly that it will be necessary to pump the pedal to stop rather than simply pressing down on the pedal. I'm going to proceed without the RPV in each circuit and see if I have that symptom. That should tell the story. I did that with my '32 Ford roadster street rod. I ran it without a proportioning valve and made a "panic" stop that locked the rear wheels. Adding an adjustable proportioning valve solved that problem.
I wish someone had already done the same conversion I'm doing on my '36 PU but that is not the case so far. Thank you everyone for all your input.
