As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ACFT MOVEMENT WITH BRAKES INITIALLY APPLIED A GROANING SOUND CAN BE HEARD UNDER COCKPIT FLOOR. WITH PARK BRAKE SET A THUMPING SOUND CAN BE HEARD BELOW PEDESTAL. EXCESSIVE BRAKE PRESS SEEMS TO BE REQUIRED TO RECEIVE NORMAL BRAKING ACTION AT TAXI SPEED. PERFORMED NORMAL BRAKE SYS BLEED IAW AMM 32-40-20. PERFORMED HYD SYS SERVICING IAW AMM 12-15-00.