What was found
DURING T/O ROLL LT ENG BLEED EICAS AND BLEED OFF LT ILMNTD FLWD BY PACK OFF EICAS/LIGHT CREW DEBRIEF: CREW STATED ON TAKEOFF RECIEVED L BLEED HPSOV STATUS MESSAGE, RAN QRH AND LEFT ENGINE BLEED NEVER RECOVERED. PERFORMED PNEUMATIC HEALTH CHECK OF HPSOV VALVE ON ENGINE 1 IAW AMM 36-23-00-745-005-001, FOUND HPSOV NOT CLOSING. REMOVED HPSOV IAW AMM 36-11-07-024-001-003 FOUND SEAL ON BUTTERFLY VALVE TO HAVE BROKE PREVENTING IT FROM FULLY CLOSING. INSTALLED NEW HPSOV ADD EMP:U408204 IAW AMM 36-11-07-424-014-003 AND AS PRECAUTION PERFORMED HEALTH CHECK ON VALVE AND CONTROLLER. OPS CHECK, LEAK CHECK GOOD. PERFORMED IDLE RUN AND ALL BLEED PERIMETERS ARE NORMAL. OK TO CONTINUE.