What was found
FOLLOWING MAINT TROUBLESHOOTING OF HYD SYS. IT WAS FOUND TO HAVE DEFECTIVE O-RING JUST AFT OF THE HYD RESERVOIR AT A T-FITTING LOCATION. DEFECTIVE O-RING DEPLEATED HYDRAULIC RESERVOIR RUNNING HYDRAULIC SYS OUT OF FLUID. THIS CAUSED THE RT ENGINE DRIVEN HYD PUMP TO CAVITATE AND DAMAGED PUMP INTERNALLY. O-RING WAS REPLACED WITH A NEW O-RING, AND ENGINE DRIVEN HYD PUMP WAS REPLACED. SYS WAS SERVICED AND OP FUNCTION CHECKED AND LEAK CHECKED WITH NO OTHER DISCREPANCIES NOTED. MAINTENANCE CARE WHEN WORKING WITH HYD O-RINGS. SUSPECT O-RING FAILURE DUE TO NORMAL DETERIORATION AND OR IMPROPER INSTALLATION AT TIME OF LAST MAINT FUNCTION PERFORMED TO THAT FITTING. (K)