As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT AFTER AIRCRAFT SHUTDOWN WITH THE PARK BRAKE SET THE BRAKE ACCUMULATOR WOULD NOT HOLD PRESSURE. TROUBLESHOOTING IDENTIFIED THE EMERGENCY BRAKE CHECK VALVE WAS LEAKING INTERNALLY. THE VALVE WAS REPLACED WITH A NEW UNIT.