What was found
"ENG 1 FUEL FILTER" LEVEL 1 ALERT ILLUMINATED APPROX 1 30 AFTER TAKEOFF. APPROX 40 MIN AFTER "1 ENG FUEL FILTER LIGHT CAME ON, THE LEVEL 2," FUEL CONTAMINATED" ALERT CAME ON , DIVERTED TO STL. REMOVED ALL THREE ENGINE FUEL FILTERS. FOUND ALL CONTAMINATED. REPLACED ALL 3 ENGINE FUEL FILTERS, MEC'S, ENGINE FUEL PUMPS, FUEL DIFFERENTIAL PRESSURE SWITCHES. REPLACED APU FUEL FILTER. DEFUELED AND ENTERED ALL 3 FUEL TANKS. CLEANED SAME. ALL COMPONENTS RIGGED, ADJUSTED AND LEAK CHECKED PER APPROPRIATE MAINTENANCE MANUAL. PERFORMED SATISFACTORY TEST FLIGHT DUE TO ALL THREE ENGINE WORK. RETURNED AIRCRAFT TO SERVICE.