Air dryer/governor/compressor issue...

That black knob looks to be the exhaust port. Is it plugged, or just some kind of fitting? Never saw that myself. If it’s a plug, I don’t think it should be plugged. Maybe it needs to be removed unless there’s another exhaust port that’s open.

 

Top of compressor has 3 lines. 1-small oil line. 1- big rubber air supply (in) hose from intake manifold. 1- big SS supply (out) air line. It’s SS because the air coming out is hot. The suggestion was to add alcohol into the SS supply hose. I’ve done that when frozen up, due to bad drier/filter/frozen spitter. I always shut Truck off, pump the air down, crack the line, make sure it’s not still under pressure before removing it. Then just pour rubbing alcohol into the line, hook it back up, start Truck. It will melt any ice, maybe clean things up? They sell “air brake conditioner” fluid. It’s expensive. Supposedly is better, as alcohol dries out seals. I wouldn’t worry about that. Anyway, I still think it’s a gauge problem. Mine have been off for years. Never showed too high, just lower on secondary. Especially since everything’s relatively new. No adjustment on govenor? Supposed to be pre set at 125 new. Not always the case.Big Road knows more about how everything works. I’m just a parts changer.

 

Yes,the size is generally stamped on the collar. Looks like 1/2”

 

Heat and extractor should get it out. Hopefully it’s not cross threaded.

 

Brass is easy with the right tool. Buy a small set or get one at a parts store.
Husky Pipe Nipple Extractor Set (6-Piece) 410-391-0111 - The Home Depot

 

If you have enough slack in the air line, you can cut it flush with the collar and take it with you to get a new one.
Use a sharp knife to cut it.