What was found
(CAN) AIRCRAFT RETURNED TO BLOCKS BECAUSE THE CREW REPORTED THE NR 2 SYSTEM HYDRAULIC PUMP LIGHTS ILLUMINATED AND THEN THE NR 2 SYSTEM QUANTITY AND PRESSURE DROPPED QUICKLY. AIRCRAFT RETURNED TO YVR AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTION REVEALED A RUPTURED LINE FOUND IN THE STUB WING AFT OF THE NR 2 SHUT OFF VALVE. LINE REPLACED, AREA INSPECTED AND GROUND CHECKED SERVICEABLE - AIRCRAFT RETURNED TO SERVICE WITH NO FURTHER INCIDENTS TO REPORT.