As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TAXIING OUT OF RAMP FELT BRAKES SLIP MOMENTARILY. ON RETURN TO RAMP, APPLIED BRAKES LIBERALLY AT TAXI SPEED AND GOT DISTINCT SLIPPAGE AGAIN WITH ASSOCIATED RIGHT YAW. BELIEVE THE LEFT BRAKE TO BE SLIPPING. DO NOT SEE ANY FLUID OR INDICATIONS OUT OF THE ORDINARY ON VISUAL INSPECTION. CORRECTIVE ACTION: REMOVED SUSPECTED FAULTY LH ANTI-SKID VALVE PN 39-865 SN 1370 AND INSTALLED REPAIRED ANTI-SKID VALVE PN 39-865 SN 1911 IAW CE-680A AMM 32-46-10.