As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE ATTEMPTING TO REPAIR A FUEL SEEPAGE PROBLEM ON THE LT ENGINE PRIMER PUMP, IT WAS DISCOVERED THAT THE FUEL SUPPLY COULD NOT BE SHUT OFF. AFTER REMOVING THE FUEL FROM THE LT AND RT WINGS. THE LT WING FUEL VALVE WAS REMOVED FROM THE SYSTEM AND DISASSEMBLED. THE O-RINGS HAD DETERIORATED AND COME OUT OF THE RETAINING GROOVE AND WERE IN PIECES ROLL UP IN THE CENTER OF THE VALVE BODY.