What was found
BRAKES FAILED ON TAXI INTO DTW ON FLIGHT 2869. STOPPED A/C WITH REVERSE ACCUMULATOR PRESSURE BRAKE ACCUMULATORS 2400-2500 NORMAL. SET PB AND WENT TO OVERRIDE ON HYDRAULIC PUMP SYSTEM, PRESSURE WENT UP TO 3000 WHEN THE FAILURE OCCURRED. BOTH CAPT AND F/O'S BRAKE HAD NO EFFECT AFTER BOOSTING THE SYSTEM PRESSURE, CHECKED THE BRAKES AGAIN AND BRAKES WORKED ON BOTH SIDES. MAINTENANCE REPLACED BRAKE CONTROL VALVE P/N HP1408100-4 REFER 409 NR 068802 FOR DETAILS. ALL CHECKS GOOD AT THIS TIME IAW SF340 AMM.