What was found
NON-ETOPS FLIGHT 88 LIH-HNL - AFTER GEAR UP, HYD PRESSURE INDICATOR SHOWED ZERO. LEFT MAIN LANDING GEAR INDICATOR LIGHTS SHOWED BOTH RED AND GREEN (UNSAFE). WHEN EXTENDING FLAPS AND GEAR, HYD SYSTEM A PRESSURE FLUCTUATED AND A SYSTEM LOW PRESSURE CAUTION LIGHT ILLUMINATED. PRESSURE RETURNED TO NORMAL AFTER GEAR AND FLAPS WERE EXTENDED. CREW LANDED IN HNL WITHOUT FURTHER INCIDENT. MAINTENANCE REMOVED AND REPLACED A LEAKING HYDRAULIC LINE BETWEEN THE LEFT HAND MAIN LANDING GEAR AND TRANSFER TUBE. LEAK CHECKED OK AND PERFORMED ENGINE RUN AND FUNCTION CHECK OF FLIGHT CONTROLS. AIRCRAFT RETURNED TO SERVICE.