On-Board Air

Adding on-board has been one of my more recent additions. After my last trip to Moab, and giving this a good long thinking through on the long drive home, I decided I was ready for this mod. I had been airing down to run trails, and then airing back up once we got back to town. Not at all ideal, and I was a little worried about overdoing it, running too little air and un-beading a tire while out crawling rocks. l had read about this happening to fellow Jeepers. Trying to swap in the spare would be pretty difficult on some of the trails we were running. It was time for me to be more prepared!

After spending a good deal of time researching the various onboard air systems available to us Jeepers, I decided on the ARB Twin. ARB has a stellar reputation in the off road community, building some of the best accessories available.

 

ARB TWin air compressor

Also known as the CKMTA12. This very robust 12V compressor was originally designed for a government military contract. The ARB twin is powerful enough to run air tools, air lockers, and of course air up my 37's. Here's a look at the details...

 

specs

- 100% Duty Cycle

- CFM 6.16 @ 0 PSI

- Thermo Switched

- 2 X Splash Resistant Air Filters with washable high-flow sintered bronze filter cartridges 

- Harness Included

- Air Locker Activation

- Tire Inflation

- Air Tools

- Made In Australia

- 2-Year Warranty

 

Typically, Jeepers will install the ARB Twin in one of two places. Either in the engine compartment, just ahead of the brake booster, or under one of the front seats. There are a few mounting brackets available for either location. 

Because I am running the Mopar BBK, which includes a bigger brake booster, the ARB Twin will not fit in my engine compartment. This left me looking at an under-seat mounting set-up. However, I was planning on running two radio systems. Both of which I had already earmarked for under seat mounting. After more research, I found WD Auto/Grabars makes an excellent cargo area mount for the ARB Twin. I really liked this location for two reasons, it utilizes an unused space in the cargo area, and the compressor is protected from dirt and heat it would see in the engine bay. 

Here's a look at the WD Automotive ARB Twin bracket...

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This is a two piece bracket, CAD engineered and constructed of heavy gauge American made steel. Here's what it looks like assembled...

On the end of the bracket, you can see where WD has provided a place to mount an on/off switch and hose connector if you prefer...

On the end of the bracket, you can see where WD has provided a place to mount an on/off switch and hose connector if you prefer...

This is the bracket I made extend the mounting holes to accommodate my reclined rear seats...

This is the bracket I made extend the mounting holes to accommodate my reclined rear seats...

The bracket is very heavy duty, with an excellent finish on it. The ARB Twin weighs around twenty pounds, and this bracket will provide a solid platform on which to mount the compressor.

This is where we are fitting the WD bracket into. It mounts up top using the existing Hard Top mounting bolts along the side...

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I'm running the War Pig seat recline kit. This meant I needed to move the bracket rearward about 1-3/4" using the custom bracket I made...

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Test fit...

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Fitting it together on the bench prior to getting it bolted in Rubi...

Here you can see the extension bracket I made, as well as the ARB manifold...

Here you can see the extension bracket I made, as well as the ARB manifold...

ARB includes a high quality wiring harness. However, for my install location, I needed to lengthen the two 8ga. power leads. I ran the leads from the compressor, along the door sills, up and out through the factory wiring hole in the firewall...

Laying out the wiring. This is one of the more time consuming aspects of this install...

Laying out the wiring. This is one of the more time consuming aspects of this install...

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Pulling wire forward...

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I pulled the plastic trim pieces between the doors at the bottom, as well as the plastic trim along the inside rocker panels. Here I am following Jeeps wiring harness...

I pulled the plastic trim pieces between the doors at the bottom, as well as the plastic trim along the inside rocker panels. Here I am following Jeeps wiring harness...

I will be using the quality ARB switch that came with my kit. I'm mounting the switch on the A-Pillar. To do this, I'll use Rugged Ridge's A-Pillar Switch Pod. The switch pod is a pretty close match to the factory textured trim, but not exact. You won't even notice after a while. It blends pretty well.

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I mounted the switch and hooked up the wiring on the back of the switch before installing the switch pod. That way, I'm only in there once for this install. I know I'll be back when I add more accessories...

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Here you can see how nicely the ARB wiring harness was laid out. This, and very good instructions made the install pretty straightforward. The harness includes wiring for the air locker solenoids. I didn't use those as they don't apply to my set-up.

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Finishing up the wiring...

This 6-pin snap connector ties the switch in with the compressor wiring. Those are in-line diodes under the heat shrink that protect sensitive electronics against current leakage. Very well thought out product...

This 6-pin snap connector ties the switch in with the compressor wiring. Those are in-line diodes under the heat shrink that protect sensitive electronics against current leakage. Very well thought out product...

Switch Pod mounted, wire hooked up. I'm ready to close up the end of the dash...

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I wanted the compressor switch to be lit and dimmable at night via my dash lights. I tapped into the dash dimmer circuit behind the glove box...

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And here's the  switch lit at night...

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Alright, now back to the compressor install. Here it is bolted in...

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You can see how nicely it hugs the wheel well, not infringing into the already limited cargo space we have in our JK(U)'s...

You can see how nicely it hugs the wheel well, not infringing into the already limited cargo space we have in our JK(U)'s...

Next, I needed to plumb the manifold to the hose connect. I wanted to have easy access to the hose and connections at the back of Rubi. I used 1/4" brass pipe and fittings for this. I also built a custom bracket to mount the hose connect to...

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Here you see how I mounted that hose connect. This has proved to be rock solid. I have the connector plumbing anchored at two places via insulated straps...

The bracket bolts in using the existing Hard Top bolt...

The bracket bolts in using the existing Hard Top bolt...

After getting the compressor installed, and looking closely at the whole set-up, I realized I could utilize the face of the bracket to mount the hose and an extra tree saw I carry for the trail. The bracket has four unused taped holes making it easy to bolt extras onto it.

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To mount the hose and saw, I used two Quick Fists 'Original' clamps...

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And here it is all finished up...

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My ARB kit included this beautiful digital tire inflator, as well as various accessory tips for blowing things off, inflating rafts, air mattress, etc.

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I'm really pleased with the way this turned out. Even more pleased knowing I'm better prepared now, having an on-board air system installed in Rubi. This is not an inexpensive mod, but I know I will be using it every time we hit the trails. I'm hoping to have a video of the system in action soon. Stay tuned for that!