What was found
AFTER PUSHBACK, STARTED NR 1 ENGINE, BLEED 1 LEAK MASTER WARNING AND EICAS MESSAGE ILLUMINATED AND LEAK INSCRIPTION BAR ILLUMINATED. INSPECTED THE NR 1 BLEED SYSTEM, FOUND A BROKEN O-RING ON THE BLEED SYSTEM JOINT UNDER PANEL 271DLW. REMOVED AND REPLACED THE O-RING IAW MM 36-11-10-400-801-A. OPS AND LEAK CHECKED GOOD. NO DEFECTS. OK FOR SERVICE.