As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) FOLLOWING PUSHBACK,CENTER HYD SYSTEM LEAK. POOL OF FLUID WAS OBSERVED ABOUT 30 FT IN DIAMETER AND A TRAIL OF SPRAY COULD BE SEEN ALONG THE PUSHBACK PATH. EICAS MESSAGES APPEARED. MOC AND DISPATCH ADVISED. MAINTENANCE ADVISED THE LEAK CAME FROM THE TAIL SKID PCU. FLIGHT CANCELLED. RESOLUTION TAIL SKID CONTROL MODULE REPLACED IAW AMM 32-71-01-401.