As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER LANDING AND PARKING AT THE GATE THE CAPTAIN ADVISED THE LOCAL MAINTENANCE THERE THAT THE BRAKES ON THE RT SIDE DID NOT FEEL NORMAL AND THE NR 4 BRAKE WEAR PIN WAS MISSING. UPON VISUAL INSPECTION OF THE BRAKE THEY FOUND THE NR 4 BRAKE DISINTEGRATED WITH ONE PIECE OF WHAT APPEARED TO BE PART OF A BRAKE DISC (PRESSURE PLATE) SITTING ON TOP OF THE MLG AXLE IN BETWEEN THE 2 WHEELS. THE BRAKE WAS REPLACED AND AIRCRAFT RETURNED TO SERVICE. NO OTHER DAMAGE NOTED.