As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT BRAKE PEDAL ON CAPTAINS SIDE, PRESS DECREASED DURING BRAKING & PEDAL WENT TO STOP WITHOUT BRAKING. FOUND B NUT AT ANTI-SKID FILTER BOWL WET. CLEANED & CHECKED FOR LEAKS, NO INITIAL LEAKS NOTED. PERFORMED BRAKE BLEEDING OF LT BRAKE SYS DUE TO SUSPECT AIR IAW MM 32-40-00. LEAK CHECKED GOOD. PERFORMED TAXI CHECK OF ACFT BRAKES WITH ANTI-SKID ON & OFF AT VARIABLE SPEEDS. TAXI CHECKED GOOD.