What was found
(CAN) DURING ROUTINE MAINTENANCE CHECK, FOUND LEFT PROPELLER ASSEMBLY HAD EVIDENCE OF OIL LEAK. UPON FURTHER INVESTIGATION LEAK WAS FOUND TO BE COMING FROM NR 4 BLADE. AFTER REMOVING THE LEFT NR 4 BLADE THE OUTER BEARING RACE WITHIN THE PROPELLER HUB WAS FOUND TO BE CRACKED AND GALLED.LEFT PROPELLER HUB, PROPELLER ACTUATOR, AND 3 BLADES WERE REPLACED DUE TO OIL CONTAMINATION AND AN ADDITIONAL BEARING RACE FOUND GALLED. AIRCRAFT RETURNED TO SERVICE.