As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A MAINTENANCE RUN-UP AND SUBSEQUENT TAXI, THE BRAKES LOCKED UP AND THE AIRCRAFT COULD NOT BE MOVED. BRAKE PRESSURE WAS RELIEVED AT THE BRAKE ASSY AND WAS FOUND THE NR 1 BRAKE MASTER CYLINDER HAD MALFUNCTIONED AND CAUSED THE BRAKES TO LOCK UP. REFERENCE AD 2002-08-02 ISSUED FOR THIS PROBLEM. THIS AIRCRAFT IS IN COMPLIANCE WITH THIS AD.