Common air leak location

I meant primary or secondary.

 

I would check fittings, plugs, and pop-off valves on the primary tank, the line to the relay valve for your service brakes and the fitting, the line to the relay valve for your spring brakes and fittings if your truck is so equipped (some manufacturers use quick release valves which get their air supply through the brake control valve), and your truck probably uses an MV-3 valve, which the tractor brake control and trailer air supply valves in one housing… definitely check that, especially since you’re losing air in both circuits, as well as your foot valve (treadle or pedal, depending on how it’s mounted) and the lines coming off of it.

 

ya give it a bubble bath, what exactly is the truck were talking about, this Cascadia
defiantly had different places to leak as my 9400"s