Converting the ARB CKMP12 to an onboard compressor

I have recently converted our portable ARB high output compressor to an onboard air setup, permanently mounted under the hood, and hope this post helps others interested in potentially doing the same.

First, I acquired the mounting plate below from DBOR (http://www.doubleblackoffroad.com/je...r-Bracket.aspx), and looked to ARB for the "feet" needed to attach the compressor's body to the plate. Strangely, ARB does not provide them as a standalone part, insisting that you purchase another blue anodised heat sink with the feet attached. The bracket was $120 plus shipping, and the new compressor surround, with feet was $28.

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The CKMP12 is fastened to its case by 4 Allen keyed bolts, and one hex nut keeping the wiring tucked neatly below the rocker switch. Upon removing those, the compressor can be removed from the case and separated from the wiring harness. The blue heat sink surrounding the compressor body can then be loosened and slid away from the compressor, to fit the newly purchased one with feet, from the CKMA12 which was intended for onboard mounting.

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ARB did not provide the hardware to attach the compressor to the plate, so I had to pick up suitable nuts, bolts and washers (stainless steel M5) on my next trip to Bunnings. Before tightening everything in place, make sure the compressor is rotated within the new surround so that the hose fitting is positioned vertically for simplicity.

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Enzed provided all the necessary fittings for this project, and even installed the hose for me without any labour charge. They are not "certified" for work on vehicles, so they asked me to look after attaching the compressor and mount to the master brake cylinder, and attaching the hose fitting to my bumper. I'm not "certified" for this stuff either, but I did it. An extra set of hands is extremely useful when fastening the compressor and mounting plate due to the weight and awkward location. Anyhow, with the compressor in place and the fittings added to your bumper, return to Enzed and they will have you sorted in no time.

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I made multiple trips to Jaycar for this project and other wiring I've added to the Jeep. The compressor's wiring harness should be reused for simplicity. You don't need to purchase the onboard compressor harness from ARB if you don't intend to run their air locker differentials. On the harness, the alligator clamps need to be replaced with battery terminal loops. Attach the compressor's power connector and red/blue pressure sensor wires to the compressor, and secure the relay included on the harness (I'll attach mine directly to the mounting plate), and then you'll have to face the switch. It's a little more complicated than other switches, due to the inclusion of the compressor's pressure switch mechanism.

You could reuse the switch that came with the compressor, by extending each of the wires (One red, two black, two yellow), fishing them into your cabin and mounting the existing switch somewhere convenient. Otherwise, if you already have a simple switch in your cabin, or like me you have an S-Pod switch controller, here's what to do: Ignore the yellow wires. I puzzled over that for a long time, and didn't butcher my harness until I had more than one auto electrician recommend the same course of action. So, tape up and protect the yellow wires, and forget about them. Then extend the red and black wires to the switch in your cabin, or attach them to your S-Pod. I promise you it works like a charm.

This cost me about $140 for the bracket, $28 for the compressor housing, approximately $120 at Enzed for the hose and fittings, and maybe $20 at Jaycar. It was also a lot of fun, started some interesting conversations, and now I can't forget the compressor at home and only have to carry ARB's hose inside the jeep.

Hope that helps!