What was found
(CAN) THE AIRCRAFT WAS ON A CREW CHANGE FLIGHT FOR A CUSTOMER, UPON START UP FOR DEPARTURE, THE FLIGHT CREW SAW THE HYDRAULIC QUANTITY FALL TO 0. THEY DISEMBARKED THEIR PASSENGERS AND CALLED MAINTENANCE. MAINTENANCE ARRIVED AND FOUND THAT THE NR 3 PUMP, SN 168405Z WAS LEAKING 2 SOLID STREAMS OF HYDRAULIC OIL OUT THE BOTTOM. IT SEEMED TO BE COMING FROM A PLUG. MAINTENANCE REPLACED THE PUMP, SN 168405Z WITH PUMP, SN 187468 INSTALLED. THE ACFT WAS THEN FLOWN WITH NO FURTHER ISSUES WITH HYDRAULIC SYSTEMS. THIS PUMP IS BEING RETURNED TO VENDOR FOR A STRIP REPORT AS IT WAS A LOW TIME UNIT.