Check out this link -
http://www.micromatic.com/draft-keg-...pid-RK-SU.html. Is it this coupler in the graphic? If so, you need to call customer service (866 327-4159) and order a replacement "Thomas valve" for this coupler. Indicate that you need a valve for the "D" style coupler.
Scott Zuhse, Instructor
Micro Matic Dispense Institute