53 sled- thanks for posting. That's the same one I used to have that was leaking. I'm still not sure if the ports on the left in your pic (front) correspond to the ports on the left in my pic...or is it backwards of that??
on a disk drum setup this is a must for piss poor brakes-wrong pedal ratios- rear brakes that don't work at all ,,,etc.
If you cant find out by the end of the day I will check tonight, I have the same unit on a 95 S10 parts truck. There is actually another valve plumbed inline with that valve on my truck, I think it is a poor mans anti lock setup for the rear brakes but I have not reseached it yet.
Still looking for an answer on this. BTW that other valve is abs related, but the prop valve is supposed to do it's job fine without it. To the other poster who commented about it not being the right valve: I chose this valve because the vehicle it came off- late 80's, early '90s S-10 Blazer- has similar brakes (GM metric front discs, 10" drum rears) and similar size, weight, and massing to the '50 Plymouth wagon I'm putting it on. I just forgot to mark the ports when I took it off at the junkyard.
Post #2 doesn't look like a proportioning valve [brake switch manifold] but #3 does..I'd get a stand alone valve and mount under floor with stem through floor so you can reach it from in the drivers seat..
Looking at your picture the left side top is the rear brake input, left side bottom is rear brake outlet. Rear brake lines in and out are 1/4", front brake in and out are 3/16". Looking in at the port holes the larger size for the rear brake lines should be easy to see.
Thanks drptop. That is what I thought. It is in and plumbed, so I couldn't look inside, but the brakes don't seem quite right and I had one of those "Did I do that right?" moments.