What was found
ACTUATOR SLOW TO LOCK IN (EXTENDED) 'GEAR DOWN' POSITION. LANDING GEAR POSITION DETERMINED TO BE UNLOCKED DURING APPROACH TO LANDING. SEVERAL CYCLES OF LANDING GEAR WERE ATTEMPTED. EVENTUALLY, THIS ACTUATOR DID FULLY EXTEND AND INDICATED A 'SAFE' CONDITION TO LAND. GEAR ACTUATOR SENT TO LEARJET FACTORY. DISCREPANCY WAS CONFIRMED. SEALS INSIDE ACTUATOR WERE FOUND SWOLLEN. REPLACED SEALS. FUNCTIONAL CHECKED NORMAL.