Ok so I've changed the master cylinder, calipers, and portion valve but if I drive my car n like 5-10min. My front brakes will stay pressed on and after bout an hr. They will release their selfs wat could be the prob.

The brake pedal itself, faulty brake lines, it sounds like some kinda pressure issue.

try this:
-block the wheels
-Jack it(make sure you do it right).
-Make sure its safe with jack stands.
-Remove the wheel.
-hopefully you have a c lamp? If not, a clamp will probably work. Or go buy one.
-Remove your caliper(straight foward for you I hope)
And Im pretty sure your pads are pressed in.
-Use your c clamp and put one side on the caliper and one side on the pad. Then clamp it so that it pushes the pads back to its spot when no brake is applied. Do this for all 4 sides. Now just go in reverse and install everything back. and it should solve your problem.
If not than its either your fluids or brake cylinder/booster.

http://www.automd.com/diagnose/

did you bleed brake system?