I’m plumbing in a trailer brake air system on the international 4400 that’s never had wir brake towing capabilities.
the supply side was easy to figure out. The service side I’m running into a issue. I was told I didn’t need to replace a the treadle valve by the dealership I got all the parts from but I’m kinda stumped on how I set up the service side so I don’t have air going to the blue glad hand when the trailer isn’t hooked up.
Can someone help explain how it should be plumbed?
Is there some sort of valve I need?