What was found
FLIGHT CREW REPORTED AFTER A FLIGHT FROM EGGW TO KEWR THAT THE A SYSTEM HYDRAULIC QUANTITY DECREASED FROM 92% TO 63%. THERE IS EVIDENCE OF FLUID IN THE RIGHT MAIN LANDING GEAR WELL AND ON THE AFT LOWER FUSELAGE. MAINTENANCE HAS DETERMINED THE SOURCE OF THE HYDRAULIC LEAK TO BE AT THE CHECK VALVE SEALS ON THE HYDRAULIC SYSTEM "A" PRESSURE MODULE. REPLACED THE P/N MS28782-19 RING (QTY 4), P/N NAS1611-214 PACKING (QTY 2), P/N MS28782-13 RING (QTY 4), AND P/N NAS1611-115 PACKING (QTY 2). THERE ARE NO PRIOR ISSUES WITH THIS PARTICULAR PART.