What was found
TOOK OFF WITH BALANCED FUEL IN WINGS 8540. A FEW MINUTES AFTER T/O IN LEFT TURN THE NR 2 WING TANK SHOWED 7.38 WITH AMBER IMBAL A FEW MINUTES LATER IN STABLE WINGS LEVEL CLIMB NR 2 TANK INCREASED TO 7.58 W/IBAL, IN CRUSE, SHOWED 7.52 THEN STABILIZED. TANK TOTALS EQUAL FUEL TOTAL AND WITHIN 200 LBS OF FMC TOTAL AFTER TANK TO ENGINE FEED AVERAGE 1000'LBAL TOD 4.89/3.92 TRIM NORMAL ONO LANDING. ACFT GROUNDED. TANK UNIT F1 IN MAIN TANK NR 2 REMOVED AND REPLACED IAW AMM 28-41-21. OPERATIONAL CHECKED GOOD.