What was found
LEAK IN NR 4 HYDRAULIC SYSTEM. ALL PUMPS TURNED OFF AND C/B CYCLED AND CONTINUED TO LEAK. CREW RPRT NR 4 HYD QTY DECREASING, UNABLE TO DEPRES- SURIZE ENG DRIVEN PUMP SO QTY CONTINUING TO DROP. CONFIRMED NO EXTERNAL LEAK AND NO HYD QTY LOSS IN HYD SYS 4. REPLACED EDP . NO HYD FLUID FROM CASE DRAIN LINE. NO HYD PRESSURE BY ENG MOTORING. REPLACED HYD SHUT OFF VALVE . CHKED OUTPUT PRESSURE AND DEPRESSURIZING FUNCTION AT MOTORING AND RUN, NO LEAK FOUND AND VLV OPS OK. OK FOR SVCE. SUSPECT VALVE SEAL WEAR.