As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AIRCRAFT RETURNED TO THE STATION DUE TO NR 1 ENGINE LOW HYDRAULIC PRESSURE AND LOSS OF HYDRAULIC FLUID GREEN SYSTEM. DURING INVESTIGATION THE HYDRAULIC PUMP HAD FAILED WITH A HOLE INTO THE HOUSING. HYDRAULIC PUMP AND FILTER REPLACED AND AIRCRAFT WAS RETURN TO SERVICE. PUMP ROUTED TO REPAIR SHOP FOR INVESTIGATION.