What was found
NOTED DURING REMOVAL OF ACTUATOR FOR ROUTINE 1,200-HOUR LUBE THAT ACTUATOR PISTON WAS CRACKED FOR ENTIRE LENGTH IN AN APPROXIMATELY STRAIGHT LINE. A NEW P/N''D ACTUATOR AND ACTUATOR SHAFT WAS INCORPORATED ON AIRCRAFT, SN R-129, AND UP. REPLACED ACTUATOR WITH SUPERSEDING P/N 129-521050-1. DAMAGE MAY HAVE OCCURRED FROM FREEZING OF TRAPPED WATER EXPANDING PISTON INTERNALLY, OR, BRITTLE METAL CONDITION. (X)