Power Front Discs Locked after Master Cylinder change

[al_wildman]

My 1962 Sport Fury Nostalgia Drag Car/Pro Street has what apparently is a 1968 or 1969 Roadrunner power front disc conversion. Brakes worked fine except back of master cylinder leaked like a son of a gun on the carpet. Traced the mc casting number, etc and found a matching mc at a local auto parts store (with engine-side fittings, etc. exact replacement). After installing and bleeding, front discs are dragging and freezing up. I suspect the plunger in the new mc is not returning to the proper position or the proportioning valve is involved. Any ideas on protocol for fixing?

Thanks

 

[al_wildman]

Just checked after everything cooled down a couple of hours. Everything is free. Back brakes are a lot easier to turn also. What in the world.

 

[mopar 3 B]

Has the residual orifice been removed on the disc brake side of the master? Will leak down over time of it is still there and let brakes turn free. Use the brakes and they will drag again. I this is the case remove the brake line at the master for the front brakes and remove the orifice.

 

[bm02tj]

also check the rod length and piston depth
if it does not return all the way the brakes will not release properly

 

[al_wildman]

I ran the little rounded bolt in about 3/16" or 1/4" and everything is copacetic. Was able to just take the mc loose from the booster without taking brake lines loose, bleeding, etc.

Thanks for your input.

 

[coloradodave]

bm02tj: Good call...