As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN BRAKING NOTHING HAPPENS UNTIL BRAKE HYD PRESSURE GAUGES READ 200 PSI THEN BRAKES GRAB HARD. SEEMS THE CAPTAINS BRAKE PEDALS ARE BAD, CO-PILOT'S SIDE BRAKES SEEM NORMAL.REMOVED AND REPLACED BRAKE CONTROL VALVE. ALL WORK DONE IAW MM.