Gauge replacement on N2 tank

[jonnie]

My gauge is leaking air through the face. It needs to be replaced. Does anyone know if i can do this myself? If so how? It is a nitro tank and is empty, I have the replacement but am unsure of how to fix.
Does anyone know why this happened, it is a perfect puncture, appears to be from air pressure.

 

[Philip]

Take off the old one(use a spanner)

Then put loctite on the bottom of the threads on the new guage and screw it in. Let it dry and hey presto.