OBA -> On Board Air Mega Thread & BS

This is how I ghetto rigged it on the OEM bumper lol


Then I moved it to my old All Pro rear bumper


but then I eventually moved it here


But then I upgraded to the ATO High Clearance bumper and moved it here with my CB antenna

 

I see what you did...thanks

 

Yup. Just drill a hole the size of the fitting. I used a step drill bit till it fit through. Used a standard quick connect and sandwiched the bumper between the male and female connectors. Used Teflon tape and some liquid sealant just in case. Came out clean.

 

Here is a reference

 

Thank you I was wondering if a set of tank straps would work well-and it looks like they might be just the ticket.

 

Your welcome.

 

I'm running a quick disconnect from my arb compressor to my front bumper. Is there any reason I don't need to use the quick disconnect on my compressor to connect that airline going to the bumper? I noticed everyone is using a fitting instead of a quick disconnect at the compressor.

 

In my experience, a quick disconnect is more likely to leak air than a fitting. There's just more moving parts. But at the same time, sometimes there's no problem at all with quick disconnects. If you're not having any issues, I wouldn't worry about it

 

Gotcha...that is basically what I was thinking someone would say. Thanks

 

Some of those disconnects are gonna get demolished if you do anything with a severe departure/approach angle! I've dragged my HC all the way up to the top of the bumper.

I just leave my QD on my tank, crawl under whenever its time to air up. Less fittings/lines = less chances of leaks.

 

Where did you get those little plastic protective caps for the QD's ? I've never seen those.

 

One reason that many run a fitting, including myself, is because we run a manifold/air block right after the compressor for lockers and to tee off the air there. Also, some have melted low quality/lower temp rated air hose that's connected right at the compressor since the air gets really hot.

 

Lowes. In the section with all nuts and bolts. It's in one of the "furniture" specialty drawers. I think they are caps for stool/chair legs.

 

Copy and pasted from my build thread

On Board Air install.

I tried to document the install as best I could and hope it'll help a few others out. Photo quality is crap as usual and mostly in the dark. If you have any questions or need anything cleared up don't hesitate to ask.

I've been wanting to do an OBA setup even before I ever planned on building the truck. Being able to run certain air tools always appealed to me. And now that I go camping/off-roading all the time, OBA has become a necessity. I still have the Sanden AC compressor I converted to grease way back when and hope to one day finish that project for the ultimate OBA setup. For now it'll collect dust till time permits an install.



Items used:

$629 ARB CKMTA12 '12V' On-Board Twin High Performance Air Compressor, Ideal for Air Lockers Locking Differentials, Tire Inflator, Air Horn, Air Tools and Pneumatic Tools.

ARB Twin compressor
ARB manifold
5 gallon AVS aluminum tank from Grunionfabrication

$39 Viair Inline Air Pressure Regulator, 0-200 psi, Black, 90150

Vair pressure regulator
Miscellaneous fitting, 3/8 DOT air line, air line cutter and water trap from AccuAir
Misc. fitting from local hardware store for quick connect air fittings/couplings
Misc. Legris Push-To-Connect nickel plated brass air line fitting from Amazon


Let's start with the tank. It has 6 ports. Two 1/2" ports and four 1/4" ports. One 1/2" and one 1/4" one each end of the tank and the other two clocked 90 degrees from each other in the center. My tank had brackets and was meant to be mounted right side up therefore the "drain" port is where the brackets are and the other 1/4" port 90 degrees from that. That's not going to work since the tank with be mounted upside down under the bed putting the drain port facing up.


So the brackets needed to be cut off, rewelded and clocked correctly. While the brackets were off go ahead and measure the distance you need to mount the tank on the "low" channels of the bed. Find the correct spacing needed for you and weld them back on. As you can see mine were cut then moved in and also rechecked 90 degrees to orient the ports with one facing down for the drain and one facing forward so it can be easily reached. It's a tight squeeze under there so if the port is facing rear you may not be able to access it.




Next you need to find where you want to mount the compressor. Again, being an access cab, space is limited so I got creative. I decided to bolt it under the bed, forward and off the the right. It is mounted above the exhaust. Now, before people start asking questions, let me explain. It's unused space and plenty of it. It puts the compressor closest to my second battery with a short run of wire. It is far enough from the exhaust to not heat it up and even if it did, the compressor gets pretty damn hot on its own when working. The exhaust also acts as a shield from water, rocks etc when driving even though it's resilient to water. It also puts it close to the 5 gallon tank I'll be running where the spare tire used to be.


It was ALMOST a perfect fit. One of those circular pieces on the rib of the mold for the composite bed needed to be notched a little to make room for the wires. You could get away with not doing this and shifting the compressor over a bit to fit bet that's where I wanted it.
vv About center of the frame is what I'm talking about.


From there I used a red painters pen and put a bunch on the ARB bracket where the bolts will be going into. The idea is to transfer that paint to the truck bed so you know where to drill the holes.


Like so


Then drill the holes through the bed. Start with a small bit and work your way up in bit size. I was able to get it so the bolts JUST fit through and had to be threaded through the bed even before threading into the compressor bracket. That keeps things nice and tight and less chance from water in the bed draining down onto your compressor. One thing to note is that the ARB bracket template that comes with he manual doesn't match up in real life. Don't know why but double check before you go using that thing.




Do the same for the manifold and connect your stainless hose. You can adjust and clock the port on the manifold to where you need it to line up. Also put in the solenoid for front air locker


Air tank mounting was next. You can put the bolts and washers in and do the same painters pen trick again to see where drilling is needed.




Again, I chose to mount the tank in the low channels of the bed


Once everything is lined up drill the holes


Drop/thread the bolts through




I may have mentioned that it's a tight fit under there. Getting all the washers and nuts threaded onto the 4 bolts was a royal PITA! It was taking me FOREVER trying to figure out how to get them all on in such tight spacing. Then I got smart. I ended up putting a large magnet on the bolts up top in the bed. From there all the washers, lock washers and nuts stood in place and didn't have gravity fighting me the whole time. Lesson learned for future projects.
These ratcheting wrenches also were a big help in the tight spaces


Tank finally bolted in


Profile view. Tucked in nice and tight with nothing hanging down below the bumper and frame




You can see the side ports, bottom drain cock and forward facing pressure relief valve at 175 PSI. Tank is rated at 200 PSI working pressure


I told you it was a tight fit. BARELY clears from hitting the ribs in the bed




Here are some of the fittings that were used. Not all pictured were utilized.


Daytime photos with tank in the rear




Hole and grommet where wires will be ran


Going into cab




Harness and air locker line connected


Water trap from AccuAir. I planned on running two water traps. One before the tank and one after going to rear regulator but the second cheap one shown a few photos up sucked so it was ditched and only used one before the tank.


Next was finding a hidden location to mount the Viair regulator.


I went with the storage cubby on the driver side. The regulator has two bolts to secure the bracket. You can see them drilled into the back of the cubby. The holes on the bottom will be for the fittings to go down into and run the air line.


How it'll sit


Perfect fit for the fittings to run air lines down


Bolted in and mounted in the cubby


Next was finding a spot to put the quick connect air fittings. One would go to the rear and the other to the front.


A step drill bit was used. Again, go slowly and check so that the air fitting threads JUST make it through to have a tighter fit.


Now the front. Thanks to @MrGrimm for this location idea.




Unfortunately I don't have many photos of all the connections at the manifold going back to the tank so bear with me. I'll eventually draw the layout on Paint to show all the connections and fittings that were used. They were all installed using some of the liquid teflon sealant as well as teflon tape. Everything was wrenched down tight. These steps are important if you don't want any leaks in the system. Once it was all assembled, use a spray bottle with soap and water to test for leaks. Bubbling will show obvious leaks.


One way check valve threaded to the in going side of the water trap then into one of the side 1/4" 90 degree fittings into the tank.






Air lines going into side cubby where regulator is. The lines come from the out going 1/2" 90 degree fitting on the diver side of tank


From there the air line runs to the rear bumper to quick connect fitting. 1/4" port on driver side is plugged.


Ran all the air line along factory harness and secured with zip ties




I tried to be creative and ran the air locker line and air line going forward through the frame and out the other end. Blue line was then routed through the crossmember behind the front differential and into the diff from there. Very little exposure to any heat or threat of getting snagged.


Clearance with exhaust in place


From side view in wheel well. 90 degree fitting from the manifold going to the rear


Rear fitting. That plastic cap can be found at your local hardware stores. I found mine at Lowes in the the specialty furniture drawer in the nuts and bolt aisle. They are end caps for chairs/stools.


Front fitting


Air line then routed through holes in the core support bracing. Side note: don't mind the shiny rear diff and front undercarriage. @RileyLAFD told me about the

$22 303 Products Aerospace Protectant Spray, UV Protection, Repels Dust, Dirt, & Staining, Matte Finish, Restores Like-New Appearance, Outdoor Cleaning Supplies 32 Fl. Oz.

Aerospace 303 stuff and how clean it makes your undercarriage look. Feel free to add any sheath in areas you feel might rub.
It'll go from this:


To this:


Behind front bumper coupling


That's it! For now... The actual install didn't take nearly as long as all the planning took. Good planning will make things go smoothly. There is still more to be done to the OBA setup which will be updated as they happen. Some things to come are a pressure gauge, additional fittings with ball valve in case of tank rupture so air locker can still be used and tires filled.

The wiring will be logged in the future. But I did cut off the fuses built into the harness and tied the compressor into my custom relay/fuse panel on a "keyed" fuse block with two 40 amp fuses. A higher AMP relay will also be swapped in. I noticed things getting hot after a long compressor run time which is expected but I would like to build in a higher safety margin. From completely empty to 5 gallon tank filled at 150 psi it took 2 minutes and 3 seconds. Then we went wheeling shortly after install and I was able to air up all sorts of tires with little effort.

Overall I am very pleased with the dual ARB compressor. The Viair pressure regulator is also well built. It's there to drop the pressure down if needed for air tools or whatever. I set it up so that the rear connector is the one with the regulator in line. Reason being was the two types of push to connect fittings that were used. The Legris push-to-connect and the AccuAir PTC fittings. The AccuAir fittings seem to be much better made than the Legris. They seem more sturdy and have DOT rated markings. But the Legris have better flow for the same size fitting. I'll try and get comparison photos of the two up. So all the stuff that might see more heat has the AccuAir fittings and the stuff I want to flow better has Legris fittings.

Which brings me to the push to connect fittings. If you take the time and prep the fittings with sealant and tape then tighten everything down, you shouldn't have any leaks. Most complain about these fittings leaking but I don't have that issue. Maybe time will prove otherwise but if the tank is topped off at 150 psi, it'll stay there all week without any change in pressure.

One thing I will keep an eye out for is how wet that compressor gets when driving in the rain. So far it has remained dry even in all the rain we've received in SoCal but just in case I picked up some aluminum sheet to make a quick splash/heat/debris guard for even further protection.

 

I agree in the tank mounting. Such a pita by yourself to get washers and nuts on. I had to have my son help me after many fucks. Super tight fit but fits well in that spot. Awesome write up.

 

Nice install! I'd probably test out your flex though. Wouldn't be surprised if the bed accidentally hit the tank with it being so close.

 

Great write up, well thought out and executed design.

@Squeaky Penguin

 

Thanx for responding. I just picked up some, and they fit perfect. They are called "Rubber Chair Tips". There were 2 different sizes, and I grabbed the smaller one.

 

Its bolted to the the bed. But the frame may hit it. But its in between the bumper mounts and there is an inch or two on all sides on mine. So I think flex will be fine. It survived hell hole. And I flexed out there. Also hit everything on rocks under the truck except the tank. I was worried about until after that trip. The down fall is im not a fan of the four small bolts through the bed. I want to make a skid plate with it welded to it.

 

Yea I have 4 bolts going through my bed. But I have a bed mat that covers it up