CountryB Posted December 27, 2019 Share Posted December 27, 2019 (edited) I'm losing air in both tanks rather quickly (over night or faster). I have not found any major leaks yet (I did find a good leak at the pressure relief valve on the air tank and plugged that) . However I think the Primary and Secondary air systems are not staying "separated". I'm trying to figure out where the two air systems (primary/green and secondary/red) tie together. Usually trucks will use a "shuttle valve" to connect the two air systems together - so if one side loses pressure the shuttle valve will slide over and block that port and continue to supplying air pressure (to whatever component) from the air side that has more pressure.I'm losing air in both sides equally fast. so I think there is a "shuttle valve" somewhere that is not closing. I cant think of anything else that would let both tanks drain equally. An Air System schematic would be useful - but there dotn seem to be any for the SMC Magnum D-series (Blue Diamond) chassis. I have three air tanks. There are two stacked tanks on the outside of frame near front of coach, and one tank in the rear over the drive line.The rear tank only has two lines (and a tanks drain line). One of those lines goes to the Relay Valve for the Tag Axle brakes. The other (black) line is the supply from the front tank. Also the Red line on the bottom tank (the one wire tied to Black line) looks to be feeding the rear Relay Brake valve for the Drive Axle.So the problem must be in the front of coach somewhere. I need to trace out the Red and Green 5/8" lines that go from stacked tanks toward the front. Does anyone have any ideas or other places to check? I have not located the air supply line coming form the Air Dryer. It's a 5/8" Green line. That could be the green line that goes into the lower tank (at the right just out of the photo). That green line goes into a pressure protection valve at the tank. I need to trace those two 5/8" lines going toward the front of coach. Edited December 27, 2019 by CountryB Link to comment Share on other sites More sharing options...
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