Co2 leak from keg coupler

[scotty2]

Can hear co2 leaking from back if hex nut, can feel it as well. Question is, does anyone know what size wrench I need to get it apart and what size o-ring(if need be) to stop the leak? I'm away from home and have to go buy a wrench said and o-ring to repair it. Thanks in advance.

 

[day_trippr]

For USA Sanke D at least the nuts are 7/8"x14 and iirc the gaskets are outside diameter 13/16", inside diameter 1/2", thickness is 1/8"...

Cheers!