What was found
(CAN) PILOT REPORTED THAT LANDING GEAR FAILED TO RETRACT. AIRCRAFT PLACED ON JACKS, LANDING GEAR SWUNG, FOUND NOSE GEAR ACTUATOR FAILED TO COMPLETELY RETRACT. REMOVED NOSE GEAR ACTUATOR, DISASSEMBLED, FOUND PISTON ORING EXCESSIVELY WORN. INSTALLED NEW ORINGS P/N 484-706 AND BACK UP RING P/N 758-053 AND RE-ASSEMBLED. RE-INSTALLED NOSE GEAR ACTUATOR, SWUNG GEAR WITH NO FAULT FOUND.