As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING REPLACEMENT OF A YAW DAMPENER SERVO, LOWER RUDDER SUPPORT BRACKET WAS FOUND CRACKED AT BOTH LIGHTENING HOLES. THE CRACKS HAD PROGRESSED ALMOST TO TORQUE TUBE BEARING FITTING. SUBMITTER SUSPECTED LACK OF USE OF RUDDER GUST LOCK AS CAUSE, AS THIS IS AREA WHERE PRIMARY RUDDER STOPS ARE LOCATED.