What was found
IAD - FLT 1239 - AFTER TAKEOFF FROM IAD WHEN GEAR HANDLE WAS RAISED, THE NOSE GEAR RED LIGHT ON THE FORWARD INSTRUMENT PANEL REMAINED ILLUMINATED. NOSE GEAR DOOR LIGHT ON THE FLIGHT ENGINEER PANEL WAS ALSO ILLUMINATED. RETURNED TO IAD AND LANDED WITHOUT FURTHER INCIDENT. REPLACED SCHRAEDER VALVE O-RING AND SERVICED STRUT WITH FLUID AND AIR. ACCOMPLISHED GEAR SWING. SYSTEM GROUND CHECKED, NORMAL OPERATION. (X)