Rear Brakes dragging

[BSG]

Its a never ending battle with this car. Let me start with what I did to get the brakes working. I started with a 4wheel drum no power brake car. Added the XV motor sports k-member and the all the Corvette susp and front brakes. Then after trying a adj purporting valve and then removing it as I couldn't see any adjustment changing the rate at which the rear brakes engaged but throughout all this I had a real hard pedal. After trying a large and small bore master, the larger one seemed to work the best and all was good but the car had overheating problems so seat time was limited. fast forward a year a new engine and a set of willwoods on the rear. Brakes are good when I roll out of the driveway but as I drive the rear brakes seem to be engaged to the point something is going to give. If it has a disc drum master is there something in them that keeps some kind of pressure on the rear? what else can it be. does any one of you Mopar guru's know of a late model 4wheel disc master cyl that can be bought from a local parts store that will bolt right up with little or no fab work? I ramble but its a 4 wheel disc that rear brakes are dragging. I have a spring on the pedal so the weight of it doesn't engage them. Its really frustrating to wrench on this thing and get little seat time. Its basically a new car. I'm sure once I get this fixed I can get some miles on it and get it ready for the fall fling here in a few weeks...

 

[Chryco Psycho]

Yes the drum master has a residual pressure valve behind the brass insert where the line seals to to retain 10 psi in the system , it can be removed with a drywall screw & A pair of vice grips , pull out the residual P valve & install the brass insert again .
I like the late 80s alum master Mopar used in virtually everything but no idea if it will bolt up to what you have now .

 

[BSG]

So take off the master remove the clip that holds the cyl that slides back and forth and makes the brakes work? Or remove the front smaller reservoir brake line from the master then pull out the brass insert, then there is a valve behind it that's kind of like a check valve? it sounds like that's probably my problem. If you could clarify exactly where that is I am gonna get right on it. This thing was my daily driver 30 years ago now I cant get it to drive 10 miles to save my a** The one thing I have learned id custom looks cool and can be but the time it takes to adapt diagnose etc, can take the joy out of it all. I', going to add some pic right now to help clarify... looks like if the valve is behind the lines that I may need to remove the master or use a very short screw?

 

[BSG]

i took the master off and i removed the brass fitting. I didn't see a valve but i measured the rod coming out of the booster roughly with what i had and it seemed long again measuring with what was available there wasn't more than an 1/8th inch of adj in so i adjusted it and slowly pumped it up and have good pedal and decent brakes i didn't go all out and slam them on but the rear definitely went to lock up before
the front but the nose did pitch down like the fronts were right there maybe a little off of what it should be. thanks for the input CP
We will see after i bleed them again this weekend.

 

[Chryco Psycho]

usually there s a small rubber "valve' behind the brass insert