Front brakes won't release

73 amx just took it out for its maiden voyage. The brakes got hot and stayed on . (Both sides) cracked a bleeder and they both loosened up stepped on the paddle again and they locked again. Disc brakes on the front drum on the back all new lines( hard and rubber ),master cylinder . never drove the car before it was restored so don't know its history. Any suggestions ? P/valve? Wrong master? Rod to long? Do you have to bleed them with the metering valve and pulled out. Thanks guys

The pedal is hard , not much travel. No booster. Tried to pull the pedal back by hand , that didn't free them up . Going to unhook the pedal and try to pull the rod out see if that works.

Do you have the proper master cylinder on the car?

Easiest thing I find when dealing with a problem like this is to loosen the master cylinder nuts while the pedal is stuck. You can back off the nuts just enough to release the brakes and measure between the master & firewall to see how much clearance you need. Remember, your application could require additional clearance of as much as 1/4 inch! I always add 1/8" additional clearance on top of what I measured and go from there. If you take all the play out, when your brakes get hot the master will drag or lock the brakes from expansion. So when you get it free (if that's the issue) get the brakes hot and then check the master again. 

While the brakes are hanging up, loosen up the lines at the master cylinder and see if they back off. Check both the front and the rear to see if both are affected. If they release, the master is the culprit. I'm on my second new Raybestos master cylinder and both hang up after they've had fluid in them. It acts like the seals are junk and are swelling up causing the piston not to return. I caught this while bench bleeding the first one and now the replacement is doing it as well.   Just because parts are new doesn't mean they're good!