What was found
WHILE TOWING THE AIRCRAFT INTO THE HANGAR TO DTW IT WAS DISCOVERED THAT SEVERAL BRAKE ROTOR DRIVE KEYS ON BOTH LT OUTBOARD AND LT INBOARD BRAKES WERE SHEARED OFF. FURTHERMORE, UPON EXAMINATION BOTH OF THE RT BRAKES HAD SEVERAL CRACKED DRIVE KEYS. THIS IS A KNOWN PROBLEM WITH THE GV BRAKES AND IS UNDER INVESTIGATION BY BOTH GULFSTREAM AND THE BRAKE MANUFACTURE. REPLACED ALL FOUR AIRCRAFT BRAKES AND BOTH LEFT INBOARD AND OUTBOARD WHEEL ASSEMBLIES. BLED BRAKES AND PERFORMED OPERATIONAL CHRCKS IAW AIRCRAFT MM. ALL CHECKS WERE GOOD AND THE AIRCRAFT WS RETURNED TO SERVICE. (M)