The pilot heard a loud bang when he retracted the landing gear. He landed the aircraft without further incident.

The technician investigated and discovered the Cessna (P/N 1281001-3) right main gear actuator body was cracked. (Refer to the illustration.) He found another crack starting where the landing gear casting attaches onto the spot face of the body. This defect cannot be seen without removing the actuator assembly. He discovered the piston assembly (P/N 9882004-1) and the sector gear (P/N 9882002-2) displayed signs of gear galling.
            

The submitter suspects the actuator body may have failed due to fatigue.

The FAA Service Difficulty Reporting Program data base revealed 22 reports of cracks on Cessna 172RG main landing actuators for the period of January 1, 1995, to May 15, 2003.

Part total time-8,129 hours.