As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS ON GEAR EXTENSION - BRAKES - AUTO BRAKE FAULT- AUTO BRAKES RELEASED. ON TAXI IN NR 1 BRAKE 580 NR 2 BRAKE 60, NR 3 560, NR 4 390. BRAKES CHATTERING - A/C HARD TO STOP. TOWED IN TO GATE. MAINTENANCE ACCOMPLISHED TSM 32-42-00-810-819-A. FOUND NR 2 TACH SHAFT BENT. REMOVED AND REPLACED NR 2 TACHOMETER AND SHAFT IAW AMM 32-42-57-401. OPS CHECK GOOD. TAXI CHECKED A/C . ALL OPS AND INDICATIONS NORMAL.