What was found
(CAN) LANDING GEAR RELAY POPPED THE CIRCUIT BREAKER, FOLLOWED BY HYDRAULIC FLUID LOW ANNUCIATOR ILLUMINATING. FLIGHT CREW PERFORMED A MANUAL GEAR EXTENSION FOR 3 GREEN. MAINTENANCE FOUND THAT THE LT MAIN GEAR RETRACT LINE HAD BLOWN. DATE OF MFG WAS 06/99. NORMAL PRACTICE IN THE FLEET IS TO REPLACE THESE HOSES EVERYTIME THE LANDING GEAR IS REPLACED WHICH IS 5 YEARS/10000 CYCLES.