What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED ON APPROACH INTO YUL DUE TO THE FLIGHT CREW REPORTING A HYDRAULIC YELLOW SYSTEM ENGINEPUMP LOW PRESSURE AND YELLOW HYDRAULIC SYSTEM QUANITY INDICATED LOW QUANTITY AS WELL. THE AIRCRAFT LANDED SAFELY AT YUL AND TAXIED TO THE GATE UNDER ITS OWN POWER. MAINTENANCE FOUND A LEAKING FITTING ON PARKING BRAKE VALVE 2579GM, TIGHTENED FITTING PER AMM 32-45-14-400-001-A AND ACCOMPLISHED A SATISFACTORY LEAK CHECK WITH NO ISSUES NOTED.