What was found
IN FLIGHT, CREW NOTICED HYDRAULIC QUANTITY AT 0, MAIN ACCUMULATOR PRESSURE AT O AND INBOARD BRAKES AT 0, NO HYDRAULIC CAUTION LIGHT INDICATIONS. RAN QRH, EMERGENCY HANDLE LOWERED GEAR. MAINTENANCE COULD NOT DUPLICATE. INSPECTED WIRING AND TERMINALS FROM CIRCUIT BREAKER M-3 TO 36VTS, NO FAULTS NOTED. HYDRAULIC INDICATION OPERATES NORMALLY. REPLACED M-3 CIRCUIT BREAKER.