As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SPRINGS PN 69-77855-1 ARE BROKEN IN THE AUXILIARY BRAKE SYSTEM. POSSIBLE CAUSE: IMPROPER HEAT-TREATING, AUSTENITE, FATIGUE AND INCREASED SPRING COIL STRESSES. SPRINGS PN 69-77855-1 ARE TO BE REPLACED WITH PN 69-77855-2 SPRINGS ON ACTUATOR ASSEMBLIES MANUFACTURED PRIOR TO SN KEO1730 PER BOEING SL 737-SL-27-090-B. (X)