Joe, this thing looks just like something you would have on your air compressor in garage. In and Out hose, plastic jar, with little rubber valve on bottom. You push valve to side and the air or water maybe blows out. You and otheres think it might be for something else and not needed on brakes of truck. Guess I'll just remove it.
Racecarl: If the brakes are working now and give that "whoosh!" sound when I lift foot off brake each time, wouldn't that mean the Relay valve is working? I can push and hold brakes, don't seem to go down in pressure that I can tell.
I'm wondering what "regulates" the pressure of application from treadle? My owner's manual says on downhills to apply brake on and off, not to partially hold like vac brakes, as the pressure will bleed off too soon. Is there any "feel" in the pedal on air brakes? Man, gotta get this rig out of garage and try to run it! Need to finish some little things first though. I got the park brake working now, feel less risky for test drive!
