What was found
JFK - FLT 0086 - EN ROUTE ORD/LHR DURING CRUISE, HYDRAULIC SYSTEM NR 1 QUANTITY WENT TO ZERO AND SYSTEM NR 1 FAILED. AIRCRAFT DIVERTED TO JFK AND LANDED WITHOUT INCIDENT. REPLACED NR 1 ENGINE, NR 1 HYDRAULIC SYSTEM UPPER ENGINE PUMP CASE DRAIN TUBE. ALSO, REPLACED BOTH SYSTEM 1 ENGINE DRIVEN HYDRAULIC PUMP, CASE DRAIN PRESSURE AND SYSTEM FILTERS. SERVICED SYSTEM AND ACCOMPLISHED LEAK AND GROUND CHECK WITH NO DEFECTS FOUND. SYSTEM GROUND CHECKED NORMAL OPERATION. (X)