As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT RELEASED PARKING BRAKE TO TAXI ONTO RUNWAY. AIRCRAFT NEEDED MORE POWER THAN USUAL TO START TAXI. HALFWAY THROUGH TURN ONTO RUNWAY, LOUD BANG WAS HEARD BY CREW, THEN AIRCRAFT ROLLED EASIER. CREW REQUESTED TAXI FROM ACTIVE, THEN RETURN TO RAMP. AFTER SHUTDOWN, THE RIGHT MAIN INBOARD TIRE WAS FOUND BLOWN, AND THE RIGHT INBOARD BRAKE LINE WAS DISCONNECTED FROM THE BRAKE BODY AT THE QUICK DISCONNECT. IT WAS DETERMINED THAT THE BRAKE LINE QUICK DISCONNECT FAILED AND POPPED OFF WHEN THE PARKING BRAKE WAS SET, CAUSING THE BRAKE TO LOCK WITH NO MEANS TO UNLOCK.