As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) HYDRAULIC QUANTITY NR 1 READ ZERO. OVERFOW CAN FULL. THIRD REOCCURANCE. FOUND RESERVOIR LOW PRESSURE RELIEF VALVE STICKING OPEN WHEN RELIEF. ABLE TO DUPLICATE BY TRANSFERRING HYDRAULIC FLUID FROM SYSTEM 2 TO SYSTEM 1 WITH BRAKE AND PARK BRAKE. RESERVOIR EMPTIED IN LESS THAN 5 SEC. HYDRAULIC RESERVOIR REPLACED.