As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED THAT THE BRAKE PEDALS ON BOTH SIDES WENT TO THE FLOOR THREE TIMES UPON BRAKE APPLICATION. THE BRAKES HAD TO BE PUMPED TO RECEIVE ANY BRAKING ACTION. MAINTENANCE REPLACED THE POWER BRAKE CONTROL VALVE AND BLED THE BRAKE SYSTEM. NO FURTHER DEFECTS WERE NOTED FOLLOWING THE VALVE REPLACEMENT. THE AIRCRAFT WAS RETURNED TO SERVICE.