What was found
(CAN) ENROUTE, FLIGHT EXPERIENCED ECAM MESSAGE "YELLOW HYDRAULIC FLUID LOW". THE QRH WAS FOLLOWED AND THE PTU AND ENG2 WERE SHUTOFF. WITH ONLY 1 BRAKING SYS AVAILABLE, THE CREW ELECT TO CALL OUT ERS BUT DID NOT DECLARE AN EMERGENCY. THE FLIGHT LANDED AND TAXIED TO THE DEICE FACILITY WHERE A CREW HAD BEEN ARRANGED TO TOW THE ACFT TO THE GATE. THE DUTY PILOT, MAINTENANCE CONTROL AND IFS WERE ADVISED. HYD Y SYS RESERVOIR LOW LEVEL, ECAM DIRECTED TO TURN OFF ENG 2 HYD PUMP & PTU AFTER DOING SO FLUID LEVEL INCREASED ABOVE AMBER BAN. B-NUT ON ELBOW FITTING OF PTU MANIFOLD FOUND LEAKING. NUT TORQUED IAW STANDARD PRACTICES. ENG CASE DRAIN FILET AND Y HP FILTER REPLACED IAW AMM 29-13-43-610-040-A & 29-13-45-610-001-A AS A PRECAUTION. NO CONTAMINATION NOTED, NO DPI`S POPPED, C/S FOR COWL CLOSURE.