What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT DIVERTED TO PIT DUE TO THE FLIGHT CREW REPORTING THAT DURING CRUISE LOST YELLOW HYDRAULIC SYSTEM FLUID ALONG WITH A HYDRAULIC YELLOW LOW LEVEL ECAM. THE FLIGHT CREW ACCOMPLISHED THE CHECK LIST AND LANDED SAFELY AT PIT WHERE THE AIRCRAFT TAXIED TO THE GATE UNDER ITS OWN POWER. MAINTENANCE FOUND UNION ON PTU YELLOW SYSTEM MANIFOLD LOOSE AND LEAKING. REPLACED PACKING ON UNION AND REINSTALLED PER AMM 29-13-15. A SATISFACTORY LEACK / OPERATIONAL CHECK WAS ACCOMPLISHED WITH NO ISSUES NOTED.