What was found
SFO - FLT 65 - EN ROUTE/JFK/SFW, DURING CRUISE, SYSTEM NR 3 HYDRAULIC QTY BEGAN TO DECREASE. ACCOMP ABNORMAL PROCEDURES FOR SYSTEM NR 3 HYD QTY LOSS AND A/C PROCEEDED TO SFO. ACCOMPLISHED ALTERNATE GEAR EXTENSION AND AICRAFT LANDED SFO WITHOUT INCIDENT. REPLACED LEFT MAIN LANDING GEAR DOOR CYLINDER. SERVICED SYSTEM NR 3 HYDRAULICS AND RESTOWED ALTERNATE GEAR EXTENSION HANDLE. SYSTEM LEAK AND GROUND CHECKED NORMAL OPERATION. (M)