Leaking Proportioning valve

[anlauto]

My customer supplied a reproduction distribution block for his 1971 Cuda and it's leaking from the bottom of the front brake block...

Found this picture on the interweb to show you what I'm talking about.

What's inside if I remove the nut on the bottom ?

How's it supposed to seal, O-ring ?

[ZippyZoo]

That's the metering valve (hold-off valve) which services the front disc brakes only.
Here are some good articles of what it does and what's inside of it.  You can also get parts to rebuild it there.

https://www.musclecarresearch.com/1970-71-mopar-metering-valve-autopsy

https://www.musclecarresearch.com/content/1970-71-mopar-metering-valve-rebuild

Pressure for the front disc brakes comes from the distribution valve into the angled port on the metering valve.  Then goes to each front caliper from the remaining ports.  I think the FSM illustrates it.  I will attach a picture from the FSM shortly.

[anlauto]

Exactly what I needed, thank you 

oh...and welcome to the best E Body web site it the world

[ZippyZoo]

Attached is how it is hooked up from the Factory Service Manual (1971 Challenger) - 'Cuda should be the same.

[Cuda Cody]

Also, when you put those brake lines in make sure to have a little grease so they don't gall on you.  Galling will almost always leak.

[toadstool]

Responding to an old post, but I have the same situation (inline tubes version also). @anlauto Alan, any idea what was the resolution? It looks like others have had similar results. Not sure I can find an original type. BTW it is a brake hold off valve

[anlauto]

I ended up replacing it altogether 

[ek3]

just a heads up. i had the leaking valve problem too. it ended up that i had to grind off .030" of threads to allow the copper gasket to "seat" fully. i know many people that have had this problem, so i am posting my findings. also, as stated lube the fittings and pull them out and keep them square when tightening them up or they will leak! same goes for fuel lines. i use wd 40 specialists with zinc gel. once galled, it is almost impossible to get them to stop leaking.