What was found
(CAN) LEFT BRAKE SYS HAD UNEXPLAINED LOSS OF BRAKE FLUID, SO AS NO LINES WERE LEAKING, THE LANDING GEAR ACTUATOR WAS REMOVED & THE SECTOR GEAR REMOVED. THE BRAKE SYS WAS PRESSURIZED WITH THE PARKING BRAKE & BRAKE FLUID COULD BE SEEN DRIPPING FROM CRACK IN THE PIVOT. THE RT GEAR PIVOT WAS ALSO REMOVED FOR INSPECTION AS IT HAD SIMILAR TIME IN SERVICE & IT WAS ALSO CRACKED IN THE RADIUS OF THE SPLINE, ALTHOUGH IT WAS NOT LEAKING BRAKE FLUID. THE CRACK WAS VISIBLE WITH MAGNIFYING GLASS. THESE PIVOTS WERE SUBJECT OF AD 2001-06-06C & SEB90 1 REV 3 , AT THAT TIME IN 2001 THIS ACFT HAD THE PIVOTS REPLACED WITH SERVICEABLE USED PIVOTS THAT HAD BEEN NDT`D & THE SK172-151 MODIFICATION KIT INSTALLED & IT HAS FLOWN 6520 HOURS SINCE 2001.