Water Pump Heater Hose Fitting?

Demonic said
If you have the room - slide an old bolt or round stock down inside that is close to the i.d., and use a small pipe wrench. I have a 12", but the mini 8" Ridge work well also. The bolt keeps it from egging and getting stuck from deforming.

Thanks for the tip, I have a Vintage Air System, I tried my smallest pipe wrench, won't get in there without taking the whole compressor mount out.