Installing Demco Coach Air Kit SM99627 And Locating Air Hose Connections On A 2018 Newmar Dutch Star
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Question:
I’m trying to install the Roadmaster 2nd motorhome kit to my air system on my motorhome. I’m trying to find the proper place to connect the air line to my motorhome. I have a 2018 Newmar Dutch Star in a XCR Freightliner chassis. I don’t have the greatest picture but I hope you can help. Thanks.
asked by: Robert L
Expert Reply:
To install the Coach Air Kit # SM99627, you will first need to locate the supply hose. The supply air hose is usually green. It will be running from the service relay valve to the braking air tank. The line will be either 1/2" or 5/8" in diameter. I believe I see the green line in your picture so if you can just verify what the line is going to and the diameter of the line you should be able to determine which one is the supply hose. Do not confuse this hose with the treadle-valve hose which is sometimes also green. This line is only 3/8” in outside diameter and should not be tampered with. So if I had to guess, it would be the larger green hose that I see in your picture.
You will also need to find the spring brake quick release valve. There should be a port on the air can labeled "emergency" or "spring". If you can find this labeling you can just follow the hose up to the valve. It should be a 3/8" air line.
I have linked the manufacturer instructions for the Demco Air Force One # SM99243 system below. Pages 9, 10 and 11 will show the steps for installing the components on the coach. There are a few pictures in there you should find especially helpful.

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Coach Air Kit for Demco Air Force One Flat Tow Brake System
- Accessories and Parts
- Flat Tow Brake System
- Second Vehicle Kit
- Demco
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