What was found
SPRINGS, PN 69-77855-1, ARE BROKEN IN THE AUXILIARY BRAKE SYSTEM. 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 S/N KEO1730 PER BOEING SL 737-SL-27-090-B.