What was found
(CAN) CREW ADVISED LOW NR 1 HYDRAULIC QTY AND WHEN THEY SELECTED FLAPS DOWN, THEY RECEIVED A NR 1 HYD ISO VALVE CAUTION AND THE FLAPS STAYED AT 0. CREW CONDUCTED A FLAPLESS LANDING. MAINTENANCE FOUND THE NR 1 ENGINE EDP PRESSURE LINE, PN 82970410-119, AND CASE DRAIN RETURN LINE, PN 82970410-115, CHAFED ON EACH OTHER AND LEAKING. BOTH LINES ALONG WITH THE EDP WERE REPLACED, ENGINE RUN AND LEAK CHECKED SERVICEABLE.