Proportioning valve question

[turbotroy]

Hey All! What is the rear fitting on the brass proportioning valve for? Is it to meter brake fluid to the rear brakes or just a port to hook the line to?
Reason I'm asking is I bought this 87 GN clone and I pulled wheels off to inspect and the rear brakes fell out in pieces. Wondered why I didn't hear it raising hell out back, but didn't think anymore about it. I Didn't bleed them as I didn't open the system, and had a good pedal.
I had the car on jackstands doing something unrelated to brakes and decided let's see how smooth (or not) these Nitto dr's roll. Get the car up to about 40 mph and am satisfied with no vibration. Hit the brakes and there's none at the rear.
I had a spare mc and installed it with no change. No brake fluid making it out back. I pulled rear brake line off of proportioning valve and nothing. The fitting that the line goes into moved when taking the line off, so I backed it out and I've got fluid coming out of that port. The reset button is where it should be I think, just a nib showing. Apologize for this being so wordy, just figured I would let anyone know what I've done to this point and the reason for the question.Thoughts/ideas? TIA

 

[tonka]

There is a pressure limiting valve in the back part of the proportioning valve that limits the line pressure to the rear brakes to somewhere around 500 psi, give or take. If you can't find a way to get brake fluid flowing through that back fitting you'll probably need a new proportioning valve.
Some years ago I removed the internal parts associated with that built in pressure limiting valve and installed an adjustable valve between the prop. valve and line going to the rear of the car. Just be aware if you go down that path you are changing how the brakes respond, for better or worse!

 

[turbotroy]

Cool. Thanks for the info. I ordered a new one today just to be on the safe side, seeing how it's brakes.