As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF FUEL WAS SEEN VENTING FROM THE RIGHT WING. FLIGHT RETURNED TO STL. FOUND EXCESS FUEL IN LT WING WHICH FILLED THE VENT BOX, AND THE VENT BOX EMPTIED ON TAKEOFF. DURING LATER CHECK FOUND A CHECK VALVE BYPASSING SOME FUEL FROM THE CENTER TO LT TANK. ACCOMPLISHED CORRECTIONS PER MM 28-20-0 PAGE 201. CHECK-C 5-31-00 STL.