MD80 FLC FOUND FUEL IMBALANCE DURING CLBOUT WHICH THEY COULD NOT KEEP CORRECTED AFTER XFERRING FUEL RESULTING IN DECLARING AN EMER AND RETURNING TO LAND.

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WITH 19400 LBS OF FUEL (BOTH MAINS FULL); FLT DEPARTED STL FOR MKE. ALMOST IMMEDIATELY AFTER TKOF; I HAD TO START TRIMMING R WING DOWN. AT ABOUT 10000 FT; WE BOTH NOTICED L MAIN FULL (9300 LBS) AND R MAIN 7300 LBS. I SWITCHED 'A' TO 'B' TO CHK THE FUEL GAUGES. WHILE STILL CLBING; WE OPENED THE XFEED AND TURNED OFF THE R FUEL PUMPS. THE R FUEL PRESSURE LOW LIGHT FLICKERED ON; BUT THE FUEL BALANCED. WE CLOSED THE XFEED AND THE R TANK STARTED EMPTYING OUT AGAIN. A 2000 LB DIFFERENCE WOULD TAKE ABOUT 5 MINS. AT THIS POINT; WE DECLARED AN EMER AND TURNED BACK TO STL; ALL THE WHILE USING ON AND OFF XFEEDING TO MAINTAIN BAL. AT ZUMAY; RWY 24; WE CLOSED THE XFEED WITH BALANCED FUEL AND LANDED 1500 LBS OUT OF BAL. NORMAL LNDG. MAINT FOUND THE WING FUEL PANEL DOOR OPEN AND THE DEFUELING VALVE OPEN. WE HAVE JUST SWITCHED PROCS. WE NO LONGER RECEIVE A SIGNED FUEL SLIP SHOWING PANEL SECURE. MAINT NO LONGER PERFORMS FINAL WALKAROUND AND THE NEWLY TRAINED GND CREWS GIVE US A VERBAL 'ALL SECURE BELOW.