What was found
HYDRAULICS 3 OFF ALERT IN CRUISE, FOLLOWED BY HYD 3 FAIL, APPROX 40 MINUTES LATER. UTILIZED EMERGENCY GEAR EXTENSION METHOD IAW QRH. RESET ALTERNATE RELEASE LANDING GEAR CONTROL LEVER IAW AMM 32-32-00-5. REPLACED NR 3 ENGINE UPPER HYDRAULIC PUMP PRESSURE LINE IAW MM 20-40-01-2, AND 29-11-22-4, OPS CHECKED GOOD, ACFT OK FOR SERVICE.