What was found
WHEN LANDING GEAR HANDLE WAS SELECTED DOWN, PILOT DID NOT GET GREEN LIGHT. CYCLED GEAR SEVERAL TIMES, UNABLE TO GET GREEN LIGHT. TRIED TO HAND PUMP GEAR DOWN WITH SAME RESULTS. THEN TRIED IT WHILE DOING NEGATIVE 'G'S', THEN NOSE LOCKED DOWN WITH GREEN LIGHT. FOUND LEFT MAIN GEAR RETRACT CYLINDER WITH A BLOWN SEAL. LEAKING BAD WHEN PRESSURE PUT ON IT. ALL OF THE SYSTEM PRESSURE WENT TO THE BAD ACTUATOR. AIRCRAFT LANDED WITHOUT FURTHER INCIDENT.