What was found
ON GEAR RETRACTION, NOSE GEAR UNSAFE LIGHT REMAINED ON WITH HANDLE UP. NLG INDICATOR WAS FLUSH, RECYCLED IN ACCORDANCE WITH POM BUT LIGHT STAYED ON WHEN ANOTHER RETRACTION WAS ATTEMPTED. REPLACED NOSE STRUT SCHRADER VALVE AND O-RING. SERVICED STRUT IN ACCORDANCE WITH MAINT MANUAL. PERFORMED NOSE GEAR RETRACT CHECK, OPERATION NORMAL.