What was found
ATB, IN CLIMB NEAR 30,000 FT GOT HYD Y RSVR LO LVL. DID ECAM PROC., RETURNED TO HNL. GROUNDED - YES. FOUND Y HYD MANIFOLD 7103JM LEAKING FROM TOP PLUG. REMOVED & REPLACED O-RING IAW AMM 20-29-00-911-801-A. LEAK CHECK OK. RESERVOIR DID NOT DEPLETE TO ZERO. SERVICED RSVR AS REQUIRED. CYCLED FLT CONTROLS WITH ENG HYD. OK FOR SVC.