As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT STARTING AN UNCOMMANDED AND UNCONTROLLABLE LEFT TURN WHILE DECELERATING. LEFT PILOT SEAT RIGHT BRAKE PEDAL "FELT LIKE MUSH" AND DEPRESSED FULLY AND HAD NO AFFECT ON BRAKING ACTION. RH BRAKES HAD AIR IN LINE. BLED LINE. NO FURTHER ACTION REQUIRED.