What was found
MAINTENANCE WAS TRYING TO SERVICE THE OXYGEN, BUT FOUND A LEAK DUE TO A CRACKED BRASS B-NUT ON THE RT SIDE OF THE CROSS-OVER FILL LINE. THEY ALSO FOUND THE SAME TYPE OF NUT CRACKED ON A SMALLER LINE, PN 129-560047-5, IN THE SAME LOCATION ON AIRCRAFT UE-90, 5/12/96. SUBMITTER SUSPECTS OVERTORQUE OF LINE AT FACTORY INSTALLATION, AND/OR NUT NOT SUITABLE FOR INSTALLATION. (X)