It turns out that installing the compressor was the simplest part of the onboard air equation. To provide an adequate reservoir for our air horns and other pneumatic accessories, we needed to install an air tank. We did just that, using a very nice air tank from a local tractor/trailer supply company. This was done before the service body was installed since we free and unobstructed access to the chassis directly above the rear axle. We thought we had the measurements all worked out. Wrong! It turns out that our first air tank installation protruded too far up above the frame rails and would not allow the service body to be installed. So it was back to the drawing board. We then decided to mount the air tank lengthwise under the bed, behind the cab, opposite of the new battery compartment. This also turned out to be a poor choice of location since we needed that area for the main power distribution center. So now we were stumped. The air tank was too large to fit anywhere else and our funds were running out. Thankfully, the great folks over at Kilby Enterprises Onboard Air division came to our rescue.
Onboard air provided us with a new air tank which they offer exclusively, as well as an amazingly crafted manifold, pressure relief valve and a superior oil/water separator. Now the hard part was devising a secure mounting for the air tank. We decided to mount the air tank directly to the underside of the Stahl service body. The trick was working around the angle supports running the length of the bed. Our first design was to span three of the angle supports but there was not enough room to bring the drill into play. Finally, we came up with the reversed mounting solution. The brackets were cut and formed at Haslag Steel using ¼" aluminum for strength and light weight. Once the holes were drilled and tapped, we installed the 135° brackets, the cross members were installed, drilled and bolted in place. Next, for extra support, we drilled and tapped the center angle support. Lastly, the holes were drilled for the air tank mounts and the air tank was secured with 5/16" stainless steel bolts. Oh, and this was on the hottest day of the year too.
Now that the air tank was in place, we could remove all of our mounting hardware and get it powder coated as well as put a new coat of powder on the air tank. Once the items were coated, and reinstalled, we were able to begin the installation of the manifold and plumbing the air lines. Once everything was installed and connected, we charged the system with our shop air compressor and found a couple of small leaks. Once those were fixed, the air tank held air and our onboard air system was complete.