What was found
DURING CLIMBOUT, APPROXAMATLY FL250-300, LOW PRESSURE INDICATION ON HYD PUMP 1, SYS A. TURNED OFF PER QRH GUIDANCE. QUATITY WAS APPROXIMATLY 65%, PRESSURE NORMAL. QUANTITY SUBSEQUENLY INCREASED, ALL THE WA TO 100%. REMAINED NORMAL QUANTITY FOR REST OF RETURN TO KSEA. GROUNDED - YES. AIR TURNBACK - OPENED #1 ENG FAN COWL TO PERFORM MAINT. PERFORMED GVI OF #1 ENG HYD PUMP, FOUND SLUDGE CONSISTENCY HYD FLUID AROUND INTERFACE OF PUMP AND ACCESSORY SECTION. NO ACTIVE LEAKS. GOOD PRESSURE ON HYD A/B W/ ELEC PUMPS. QUANTITY OKAY. SAFE TO MOVE. CLOSED #1 ENG FAN COWL. J MOORE 30353 1024-2023. REF LP PAGE 60735837 FOR REPLACEMENT OF #1 ENG EDP.