71 Roadrunner 4 wheel disc conversion questions

[jonny0666]

Recently I did a 4 wheel conversion on my car. I used the Right Stuff conversion kit from Classic Industries. Originally a 4 wheel drum car. Swapped out the booster and master cylinder for disc/drum. Then decided to go full balls to the wall and got the rear conversion. Slapped it all together and now the rears drag. I’ve read about 20 different threads about this but all have different variables. Anyone have any tips or solutions? I’m running the standard drum distribution valve with metering block for the fronts. I’m contemplating putting an adjustable proportioning valve in because I’ve read I should. I’ve also ready you modify the distribution valve for the rears. Anyone else do this on a 71 b body? I’m not pushing major power in the car. It’s pretty much a cruiser. Any help would be much appreciated. Thanks.

 

[moparmarks]

What master cylinder are you using?
I just tee the front lines and use an adjustable valve for the rears

 

[jonny0666]

I’m using a drum/disc MC. So you just by-pass the distribution valve and use an adjustable instead?

 

[moparmarks]

Ok that master might have a residual valve for the rear that is not letting the pressure release completely and is causing the rears to drag. You can remove the valve out of the port for the rear line.
I use a later master that has a common reservoir for front and rear.

 

[R/T Boy 67]

Make sure there is not a residual pressure valve in the front outlet, which goes to the rear brakes.

 

[pnora]

By dragging are they hydraulically being held? If so crack the lines and see what part of the system is holding them applied. Is the master push rod length correct? To long and it mat not be releasing the master. All the proportioning valve a distribution valves to is meter fluid on application. They can not hold pressure.

 

[jonny0666]

Yeah I’ve read that you can use a paper clip and burn open the residual valve... or is it worth it to try and remove it?

 

[moparmarks]

Myself I just use a steel tee for the front and an adjustable valve for the rear. I've done several cars this way. Very simple and efficient setup.

 

[jonny0666]

... if it works. I’ll give it a shot. Thanks. And I’ll look into the master as well.