What was found
FUEL DRAINING OUT OF ACFT LT MASK. FUELERS WHERE FUELING AND APU RUNNING AT SAME TIME. AFTER FUELERS STOP AND APU SHUTDOWN. RAN APU AGAIN NOTED NO FUEL. FOUND HST LINE LEAKING. TANK TO REMAIN EMPTY. INFO BASED ON ORD INFO, SUGGEST CHECK OF STAB PUMP SHROUD AND EXPOSED LINES IN STAB COMPARTMENT, TO ISOLATE SOURCE OF LEAKAGE. LONG FUEL LINES IN SHROUD MAY BE OKAY. REPLACED AFT HST FUEL LINE. PRESSURE CHECK HST XFR LINE, PASSED. REPLACED HST FUEL LINE MIDDLE SECTION AFT OF PRESS BKHD. PRESSURE CHECK XFR LINE PASSED. SECURED HST SHROUD LINE AT MIDDLE SECTION AFT PRESS BKHD. FEED LINES REPLACED STA 1242.7 TO STA 2412 AND HST X-FEED LINE 2412 TO HST TANK REPLACED. COMPLETED TASK. PRESS CHECK GOOD PER MM.