As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON TAXI OUT APPLYING LIGHT BRAKING, THE LEFT BRAKE MAKES A CHATTERING SOUND AND VIBRATES. GOING SLIGHTLY FASTER THAN NORMAL TAXI SPEED AND APPLYING HEAVIER BRAKING, THE AIRCRAFT PULLS TO THE RIGHT. PERFORMED BLEEDING OF THE POWER BRAKE SYSTEM, PERFORMED OPERATIONAL CHECK WITH NO FAULTS FOUND. ALL WORK DONE WITH REFERENCE TO AMM-32-44-00.