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netlohcs 01-23-2012 12:23 AM

ARB CKMTA12 Compressor install - writeup and pictures included
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Hello all!
I have enjoyed being part of this jeep community for a while, mostly taking in information and asking questions. I have really appreciated everyones help so far, and as such I was wanting to add to the information base here at wranglerforum. ARB has recently come out with a new dual pump compressor, which I recently purchased and installed. I did a short (maybe it will turn into long? :) ) writeup regarding my experiences with it.
The model number of the compressor is the ARB CKMTA12. They also make a 24 volt version. Flowrate is just over 6 cfm, and they claim that you can air up a 33" tire in under a minute with this model. ARB also claims that for its compact size, there are no other compressors on the market with more output. Additionally, it has a 100% duty cycle.
One of the first drivetrain components I wanted to add was lockers front and rear. In the end I settled on the ARB airlockers based on the quality, and good reviews. Additionally I liked the idea of having on board air, and being able to air up my own tires, or possibly help someone in need air up theirs.

I researched different compressors and knew from the beginning that I would most likely want to stick with one of the ARB models. When I learned that a newer, larger unit had come out recently I knew I wanted it. The idea of not having to sit around waiting while I air up tires sounded great. Granted the compressor was quite a bit more expensive but I felt that the additional performance was worth the cost. It was also 100% duty cycle, something I liked.

The big issue though, was fitment. I talked with someone at Burnsville offroad (burnsville MN) who informed me that he didn't think the compressor would fit under the hood where they usually mount the smaller ARB compressors (on the tray beneath the brake booster). Additionally, he said, even if it did fit, it would really suck to try and work on any of the fittings/solenoids. One thing I don't think he realized though is that unlike the other two ARB model compressors, the manifold that you mount the solenoids to is not included on this model, and is a seperate part. The downside with this is that you have to buy another part (on top of the already fairly expensive compressor), but the upside is that you can mount it in a location that makes it easier to access/work on the solenoids.

Not fully believing what the guy from Burnsville had to say, I build myself a "test model" out of some 3" thinwall PVC and 1/2 mdf. I tried making it as close as possible to the factory dimensions given by ARB. The verdict: I think it will fit. I knew it was going to be DARN close, but I really REALLY thought I could get it to fit. And with that, my mind was SET :)

The compressor itself was ordered from, for $455 and free shipping. As stated, the manifold is a seperate part that ran me another $50 bucks. shipped me the compressor in JUST the ARB box, not even taped shut! I could hardly believe it. Anyone along the UPS line could have just opened it up and put a big hunk of metal or something else in its place, and sent it on down the line. Fortunately this was not the case, and it showed up at my shop unharmed. The manifold arrived in good shape also.

I unpacked the compressor and sorted out the 3 different wire looms. I also pre-plumbed the manifold (more on that later).
Picture one is of the compressor, freshly out of the box. Notice the fitting near the center (currently has the red plug in it), this is the output fitting of the compressor.

Picture two is of all the wiring looms. The instruction manuals are very comprehensive and make all of the wiring information very clear

Picture three is of the manifold, which I had pre plumbed with the two solenoids.

Next post, the install begins!

netlohcs 01-23-2012 12:31 AM

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To begin with, I "prepped the patient for surgery" so to speak :) There were quite a few things in the way, and I began methodically moving them. First off, the cruise control module needed to be moved. After unbolting it, I determined that it would probably be best if I actually permanently relocated it. I disconnected the 4 wire plug, after which the module itself was on quite a long tail (vacuum line and throttle cable) and could be located pretty much anywhere I wanted. I determined that mounting it close to the battery would be best. I didn't take any pictures of this, maybe i'll take a few tomorrow.

Additionally, I unclipped some of the wires that were in the way (brake fluid sensor wire, and a few others) just to get them out of the way. There was a larger plug that ran wires up towards the front, I would assume this would be for headlights, turn signals, horn, etc. I also unplugged that one temporarily, just to give me more room. Once that was done, I had a clearer view of the tray I wanted to locate the compressor on.

The first picture is of the tray before anything is moved.

The second picture is after I relocated the cruise control and disconnected the misc. wiring harnesses.

netlohcs 01-23-2012 12:39 AM

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From the beginning, I knew that the clutch master cylinder would be in the way. I wasn't sure exactly how much work it would be to loosen the two bolts that hold it in, I was expecting the worst. They are pretty inconvient to get to, and you have to kind of lay on your back and one-hand it at the same time. Thankfully, they ended up being very easy to get off. Once The two nuts were removed, I was plesantly suprised with how easily the cylinder pushed out of the firewall, giving me some much needed clearance.

Additionally, this CKMTA compressor has a black metal heatshield that resides between the compressors. (you can easily see it in the very first picture that I posted). Attached to this shield is the cooling fan and all of the wiring for the compressor. The shield is designed to be easily removed (to access the pressure switch and work on wiring if needed). However, removing the metal shield turned out to be very advantageous for me for test fitting purposes. In this picture, you can see that the shield has been removed. Once the shield was removed, the compressor slid down into the hole with relatively little effort.

I could tell though that once the shield WAS on, it was going to fit TTIIIITE and as such, I would only want to put it in there ONCE with the shield on. That one time would be the last time ;) Additionally, because of the way the heat shield hinges on/off the compressor, installing it onto the compressor after the compressor was installed into the vehicle was not really an option.

Picture one shows the clutch cylinder after it has been loosened from the inside.

Picture two shows the compressor on the tray during its initial test fitting.

netlohcs 01-23-2012 12:51 AM

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Up next was to begin tackling the wiring. The battery cable included was pre-loomed and included two fuesholders on the power wires. Fortunately the included power and ground wire was pretty much the exact right length for the location that I had chosen. I located the plug down by the tray, giving myself an inch or so of slack to spare. I then routed the wire following the factory loom across the top of the firewall. I plan on installing an amplifier for my stereo system soon, and decided that I would run that now, since I would most likely be making the rubber boot fairly difficult to access.

I also run the included loom that goes to the switches/accessory wire/ilumination wire into the vehicle through the rubber grommet located just above the tray. This harness is VERY long, probably so you could install the compressor somewhere much farther away from the dash. In any case, I had plenty of wire to work with.

My biggest concern during the install was the permanent mounting of the compressor. There are 8 threaded inserts on the bottom of the compressor, but I didn't really know how I was going to be able to utalize them. After taking a peek underneath the jeep though, I realized that I acutally got really lucky, and that if I could manage to get the holes drilled into the tray in the just right spots, I would actually be able to put the bolts in from underneath the vehicle. Granted, I wasn't going to be super easy, but then again this whole install is more about saving space than being easy, so I was pretty excited that I had found a way to mount it.

ARB includes a paper template for the hole locations on the bottom of the compressor. I really took my time on this part, as tolerances are TIGHT! the compressor only has about 1/4 of an inch play between the brake lines and the fireall, and only about 1/2 inch of play between the large wire loom coming out of the firewall and where the wheel well starts coming up. As such, I marked, measured, checked, re marked, re measured, and checked again. You get the idea ;)

Once I was confident that I had the holes EXACTLY where I wanted them, I finally drilled.

Picture one is of the battery wiring, fairly straightforward.

Picture two if of the paper template while I was working on getting the hole locations worked out.

Picture three is of the holes after they had been drilled. It is worth noting that the two near holes and the front inside hole were drilled from the top, but the hole that is directly under the brake cylinder was actually drilled from the bottom. Again, when I did this I really took my time and made sure that everything was lined up properly.

netlohcs 01-23-2012 01:01 AM

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With the mounting holes drilled, I felt as though I was getting fairly close to the final installation of the compressor with the heat shield on. However, before I did this I wanted to make sure that I had a good location for the manifold to be installed. After some measuring and planning I decided to create an aluminum bracket (really just a piece of flat aluminum) that mounted the manifold to the top of the compressor.

To do this, I drilled 3 holes in the top heat shield on the compressor and installed three 1/4" bolts in these holes. Fortuantely these nuts did not interfere with any clearances during the installation of the compressor, as only the lefthand side of the compressor was really going to be a tight fit. These 3 bolts can be seen in the first picture.

Once I was confident that I had a good location for the manifold, it was time to install the compressor for the last time.

Let me say this, with the heat shield on, it is a TIGHT, TIGHT fit! if the compressor was even 1/4" taller, or 1/4" longer, it probably wouldnt fit. I actually had to ever so gently pull out on the fender to get it to "pop" down. It did though, and I was super happy when I realized that it DID in fact fit for sure, and my hard work was going to pay off ;)

Picture one shows just how tight the compressor install actually was. Note how close the bottom black bracket is to the edge of the fender wall. A little tugging and kind words though, and it did go in :)

Picture two shows the compressor after it was positioned on the tray. Note the three bolts I will be using to mount the manifold.

netlohcs 01-23-2012 01:04 AM

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Once the compressor was located in its permanent home, I began installing the bolts to secure it underneath the vehicle. Because the factory tray is fairly thick, I had to go to home depot and get slightly longer M6 bolts. I also added teflon washers to try and isolate the vibrations a little bit, but I doubt that they did much :)

Picture one shows the tray on the outer side of the vehicle.
Picture two shows the tray on the inner side of the vehicle. This picture was taken when only one bolt was installed, with one remaining to be installed.

netlohcs 01-23-2012 01:11 AM

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After the compressor was bolted down, all that was remaining was to plug in the wiring and mount the manifold. The steel braided hose that came with the manifold is very nice, but is EXTREMELY inflexible, it took a little while to figure out a way to get it to run the way I wanted it to. I also took care not to tighten down the nuts on my three mounting bolts TOO tight, as I didnt want to spin the nuts underneath it.

I also had to screw on the two small airfilters on the end of each compressor. This design would allow you to locate the compressor intake somewhere higher up if you feel that would be necessary. I do not plan on traversing any water even CLOSE to this high, so that was not necessary for me.

This picture shows my setup after the manifold was bolted down and plumbed up. I like where the fitting is located that I attach the airhose to. It is easily accessible yet not in the way.

netlohcs 01-23-2012 01:14 AM

That pretty much covers my install up to this point! I hope you guys enjoyed my writeup/pictures :) Up next for me is to get my ARB airlockers installed, they are patiently sitting on the floor in my office, waiting for me. I can't wait to get to use them!! I just might have to go try and get stuck somewhere just so I have an excuse to try them out. If you guys have any questions/comments on the compressor install feel free to ask, I would enjoy other peoples insights.

Overall I am very glad that I decided to get the bigger dual compressor unit, as it ended up fitting VERY well in the space provided. Additionally, everything is easy enough to get to that any type of servicing that I may need to do down the road is going to be very managable. I really hope I come upon a little old lady in a parking lot sometime soon with a flat tire so that I can swoop in and save the day ;)

netlohcs 01-23-2012 07:45 PM

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Here are a few pictures of the cruise control relocation that I did. It was fairly straightforward -

Picture one shows the 4 wire harness that I cut, and then used 4 conductors to extend the harness.

Pictures two and three show the new location of the cruise control module, near the battery.

netlohcs 01-24-2012 04:59 PM

Hmmm any comments from anyone? I was hoping someone would say something...

nicolas-eric 01-24-2012 06:40 PM

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When I read this thread I know why I habe two CKMA12 compressors.
They are as strong as the CKMTA12 but way easier to install.
After only 1-2 hours they were under my hood.

chop110 01-24-2012 09:05 PM

Nice writeup! Where did you order the manifold?

netlohcs 01-24-2012 09:28 PM

The manifold I ordered from quadratec.

Nicolas-eric, is the CKMA12 100% duty cycle? I don't remember seeing if it is or not. You are right though, two of those will give you almost as much output as the CKMTA12. I really wanted everything to fit everything in the smallest space possible, and was willing to take a little extra time to do so, just depends on what you want yourself :)

urbanZ 02-23-2012 03:18 PM

Man I really did not think that would fit under the hood.. Good job.. :punk:

I ordered the compressor and manifold both from 4wheelparts.

When I got the compressor home and started staring under the hood, I started looking for other locations..

I started to think about putting it under the drivers seat, but hod no easy way of wiring or placement for the manifold.

After moving it around for a while I decide on a final spot..
Inside the trunk. It was in the Jeep when bought and has spent more time out then in the Jeep. Well it now has a purpose..

NizmoTJ 02-26-2012 10:05 PM

sorry, this might be dumb question but what is the purpose for the "manifold"?

netlohcs 02-26-2012 10:24 PM

The manifold provides you with a tiny little "tank" essentially - if you have any little leaks in your air lockers (they all pretty much seem to) your compressor would be kicking on almost constantly if there wasnt at least SOME sort of resivour.

Additionally it provides you with a location to thread in fittings for the solenoids that operate the airlockers themselves.

XMRacer 03-10-2012 05:54 PM

Thanks for this write up, was at 4 wheel parts today contemplating this exact install. Now that I know it can be done, I'm going to give it a shot.

Kf4pwb 08-19-2012 11:52 AM

So if im not running the arb lockers do i need the manifold?

Full Spool 08-19-2012 12:20 PM

Little concern about placing it on the exhaust side of the engine well. My compressor gets hot even in the stock airbox location.

clampphil 02-28-2013 08:46 PM

How did you mount the switchs for the air compressor, front locker and rear locker Netlohcs. I know this is a late in asking

SS Adrenaline 02-28-2013 08:59 PM

Very nicely done. Do you have any pictures of the switches installed for the lockers?

clull05rubi 03-05-2013 06:39 PM

The dual had like 2 or 3 big cooling fans on it and a nice heat sin . Heat wont be a problem.

needaglock 03-05-2013 07:19 PM

Great write up! I hope you don't mind me cross-posting this question into your thread. I'm looking at this model for my 06 rubicon, does anyone know if it would be possible to use this to replace my compressor for the stock lockers, and could I wire it in to the factory oem switch? I want to be able to air up tires without shelling out for a warn dual force.

DarthLEGO 03-06-2013 09:35 AM

Awesome write up. I had no idea I could safely move the CC Module. I got one of the Smittybuilt Compressors that Amazon had "on sale" a couple of weeks ago and was trying to figure out if I could squeeze it into the same location.

I might actually have a little wiggle room now.

suicideking 05-08-2013 11:59 AM

Nice write up!

How do you like the compressor so far? Is it pretty fast at airing up? I'm thinking of getting it.

Jerry Bransford 05-08-2013 12:34 PM

VERY nice review & great photos too! I know a ton of people will find it useful, I would certainly refer to it if I ever replace my current crappy Rubicon lockers with ARBs which would be great if I could afford them at this time.

PieMan 01-05-2014 05:22 PM

so a couple of years later is there any issues with heat? and i saw that you removed the back 2 bolts of the plate itself did you ever put them back in?

Mike05LJ 05-06-2016 08:00 AM

Exactly what I was looking for
I have been trying to figure our which compressor to buy and where to install it. I was leaning towards the ARB Twin and this exact location but did not think it would fit. After reading your post I now know what to do. Thank you very much and great write-up. Very detailed and the pics really help.

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