What was found
CENTER HYDRAULIC RESERVOIR LIGHT AND CENTER HYDRAULIC QUANTITY EICAS MESSAGE WITH AN INDICATION OF .38RF CENTER QUANTITY. PRESSURE WAS STABLE AT 2890 TO 2910 POUNDS PER SQUARE INCH. BOTH QUANTITY AND PRESSURE REMAINED UNCHANGED THROUGHOUT APPROACH AND LANDING ON SHORT FINAL. THERE WAS A PRONOUNCED ROLL TO THE RIGHT. ALL FLIGHT CONTROL INDICATIONS WERE NORMAL. LEFT AILERON WAS REQUIRED UNTIL LANDING. LANDED DFW WITHOUT INCIDENT. REPLACED CENTER SYSTEM PILOT AILERON SERVO. SERVICED CENTER HYDRAULIC SYSTEM WITH NO LEAKS FOUND. REPLACED CENTER HYDRAULIC FLUID QUANTITY TRANSMITTER. SYSTEM GROUND CHECKED NORMAL OPERATION. (CLOSED)