Time has finally come for onboard air and water, not wanting to take up interior space I started looking under the van for options. I didn't like outside the frame rails at the back since there is so much dirt and stones thrown up from the tires in there, my drivers side has batteries so that only left the rear area. Just behind the axle I have reserved for a 2nd diesel tank so that only left the spare tire area. This was really the last location I wanted to use as it's a lot of weight to hang behind the axle, but it was the only area available.
So after cutting out the spare tire chassis member, (that was a job all on it's own) I set about designing a way to hold Air tank/ 2 compressors / Water tank & water pump. Initially I wanted to use UJoint skidplate kit, but I really didn't want to cut out the remaining chassis member and weld in a new one, so that kind-a ruled out that kit.
So in the end I decided to make my own from stock I could get locally and tools I had available. If I had access to a decent bending machine, my design would have been different, but I don't.
I use 2"x3" steel box section as frame rail extensions, and 3/4" box section for the support braces. The 2x3 were notched so the 3/4 box section actually goes inside the 2x3's, and they are also welded inside. (just for extra strength as I guess all the parts will be ~250). Once the cross member were welded, I capped the 3x2's to stop and crap getting inside.
There is some kind-a reason to the vertical cross braces, they hold the tank and compressor.
All mounted up. I new I could fit a bigger tank, but I decided to pick a 2.5gal 200psi tank as it gave me more volume that a 3 or 3.5tank at 150psi, and the compressors are rated for 200psi.
Now I have the exact size, I can order up the water tank, I can make a 16gal fit easily with a pump, and just make a 20gal fit with pump, but think pluming will be a real pain with the 20gal. I would have preferred to mount the water tank further forward wherethe compressors & air tank are, but there is a body cross-member there that limits the height, you can just see it in the above picture.
Since the water tank will be ~150lbs I decided to brace the extension that's not really supported. Below you can see some angle I bolted to the tow hitch to brace it.
Now I'm just waiting for the tank and pump to come so I can mount them up. After that, there will be an aluminum skid plate bolted to the whole frame so protect it all from debris. In the very first pic you will see some tabs welded to the frame, they will be drilled and tapped to hold the skidplate in place.