Contact 45PSS or Bert Saunders at www.graflex.org. Bert is a retired Graflex/Graphics repairman who fixed cameras for people in the forum in the past, however he no longer is able to do the repairs himself but he may send instructions via email. 45PSS does repairs.
If the Graphex shutter is sticking, remove the front and rear elements. Likely put graphite on each side and cycle the shutter many times at each shutter speed. Use compressed are to blow the remaining graphite off the shutter before replacing the front and rear elements. It took me at least 100 firings for each shutter speed to get every shutter speed working and working consistently.