Jerry, Thanks for the quick reply...
The leaking part in question is tee'd off of the brake pedal valve. It looks like it has a small (1.5") diaphram and goes no where else so I assumed it was some sort of pressure regulating device.
The brakes had been leaking down when the engine was not running and this was the only "hiss" I found. Well, at least before the main line to the tanks blew yesterday afternoon. I was in pretty rough terrain and it looks like it has been rubbing on the frame. I figure it's time to go thru the system.
I'll get a picture this afternoon.
Dan