Repurposing Suspension Air Compressor

[OverlandExpy]

Been searching online and haven't found much about this topic so I figured I'd start a thread here. I've been doing a lot of research on how to turn my 04 EB into a decent overlanding vehicle, and the plan is eventually to have front and rear lockers. Air lockers are a thought, and even if I don't go that route having access to compressed air can come in handy in plenty of other ways. Since I am replacing my air suspension with coilovers, I was hoping to repurpose the suspension compressor into a general air compressor. I have a few spare tanks I could use, but haven't found anyone who has tried this before.

Was wondering if anyone here has ever heard or seen anyone do it. Any links or info would be greatly appreciated!

 

[riphip]

Would probably be a slow fill/recovery, depending on size of tank. Put a gauge somewhere at the dash and demand switch on the tank(s) since original switch just powers compressor when level switches (either front or rear) kick on compressor.
Very do-able but I would use larger/faster compressor

 

[OverlandExpy]

I have the shop repair manual for my expy, and it looks like the compressor has a 150 psi pressure release valve, so I think compressor would be more than powerful enough. The switch would need some custom wiring or else it would be running constantly. I found a pin-out for the compressor system and could wire in a switch that could turn it on and off on demand. A pressure gauge would definitely be part of the system if I end up going through with it. I am concerned about the connectors for the air lines, however. I am not sure if they are a standard/universal fitting or a custom fitting.

I'll try to keep everyone updated on my progress but I was hoping someone had done some aftermarket work on their air suspension system.

 

[riphip]

You can install an adjustable pressure switch to control demand/regulated pressure in tank. Same thing regular air compressors use. Use the same wiring but splice switch at ground wire for pressure switch.
Your front and rear sensor switches may use this wire now.

 

[OverlandExpy]

Starting to work on this project now that I finished up my rock sliders. I'll update my other thread with pics of that process soon.

I drained and removed my windshield wiper fluid reservoir, although I dropped one of the bolts that secured it between the compressor and the wheel well and can't get it out lol. First going to try to jump my compressor directly from my battery. If that works I have plenty of wiring and an aircraft switch that I can wire up the compressor to, so I can turn it on and off with the flip of a switch in the cab.

I pulled out all of the push to connect air lines from the rest of the truck, and I'll repurpose it to route it to a tank I'm buying. They sell air tanks for use with air horns and whatnot, and I can get a 3 gallon one that goes up to 300 psi with 2 ports for $50. There's only one air line coming out of the compressor, so I'll route that to a push to connect to 1/4 npt fitting into the tank, and then I'll route a regular 1/4 line out of the other port in the tank, and I'm planning on routing a pressure gauge back into the cab some where. Maybe put a pressure relief valve somewhere in the system, but the shop manual says the compressor has a pressure relief valve built into it, so that may be redundant. Ill also route a line to a quick release fitting that I'll install in the bumper. That way I'll have a port I can use to air up the tires with quick and easy access from the outside of the truck.

Was wondering if anyone sees an issue running the compressor right off the battery. The switch I'm using is rated to 15amps so if anything goes wrong that'll function as a fuse lol.

I'll post some pics later this week, not too much to see until I buy the tank and the fittings though. But everything hinges on being able to jump the compressor off the battery.

 

[OverlandExpy]

Quick question for anyone who has jumped the compressor before.. there are four wires coming off the compressor, I know two are the hot/gnd wires for the compressor itself, but was wondering what the other two wires are? Looks like it is maybe the vent solenoid assembly, but I thought there was a mechanical pressure relief valve in the compressor assembly.. Is the vent actuated by the solenoid? I guess it is not a huge deal if it is, I could just put a 200psi pressure relief valve on the tank or something.

Thanks in advance!

 

[ExplorerTom]

This is just a guess, but I would imagine it has a very low cfm.

 

[OverlandExpy]

I plan on putting at least a 3 gallon tank in the truck, if not bigger. That way I can run the compressor intermittently when I'm on the trail heading back to the road and fill up the tank to 150 psi or so, and be able to fill up the tires pretty quickly from the tank and not have to worry about waiting forever for the compressor itself to directly fill the tires

 

[OverlandExpy]

Alrighty, first step done! Way easier than expected too. Just took out wiper fluid reservoir, disconnected the main plug to the compressor that had the + & - wires, and wired it up straight to the battery for a quick test run. I've already removed most of the push-to-connect air lines from around the frame, and my model compressor only has one line going out from the compressor instead of two, which I've been seeing around on OEM replacements and other model year expys. Makes it easier on me to put in the new system though! Air came out of the line right when I fired it up. As you guys have suggested, the flow is not great though. I think I'm going to stick it out though, worse case scenario I install the whole system, and the compressor isn't quite cutting it. In that case I'd just remove the compressor, buy a better one, and figure out how to mount it into the same place while using the existing wiring/air lines. Anyone see any glaring issues with this plan?

Things I'm planning on buying for this project are a 3-5 gal 300 psi tank, a mechanical pressure relief valve to build into the system, and a wire with a built in fuse that will run to the switch I already have. I've got a lot of pneumatic lines around my shop I can use, and I also plan on repurposing the air lines for the suspension that I pulled off the frame. As always I'll keep posting with any updates!

 

[OverlandExpy]

Small update, bought a 5 gallon tank. Dimensions are appx 21x12x10. Any ideas of where to mount it?? Was thinking of where the spare used to be, but that spot seems susceptible to being dropped on a rock when I'm offroad. Unfortunately both of the arm rest/wheel well areas beside the third row seating are all full of stuff. A/C I think on the passenger side, and a bunch of electrical crap on the driver side. Also have an aircraft switch with one of those red covers, can't wait to have that and a pressure gauge in the cab.

 

[tommyddsr]

Quoted from above: Was wondering if anyone sees an issue running the compressor right off the battery. The switch I'm using is rated to 15amps so if anything goes wrong that'll function as a fuse lol.

Back to your question from above, YES, you should use a fuse on the power. Setting your switch on fire in the truck is not a good fuse plan.

 

[ExplorerTom]

Was thinking of where the spare used to be, but that spot seems susceptible to being dropped on a rock when I'm offroad.

If you get a big rock up in that area, it’ll rip your bumper off anyway.

And in my ~10 years of offroading, I’ve never had a big rock there. To get a big rock up in that area, how would it clear everything up under the truck ahead of that area?

 

[OverlandExpy]

Quoted from above: Was wondering if anyone sees an issue running the compressor right off the battery. The switch I'm using is rated to 15amps so if anything goes wrong that'll function as a fuse lol.

Back to your question from above, YES, you should use a fuse on the power. Setting your switch on fire in the truck is not a good fuse plan.

Definitely. I went to Amazon and bought some in line fuses already. I'll make sure the fuse is on the forward side of the firewall lol.

 

[OverlandExpy]

If you get a big rock up in that area, it’ll rip your bumper off anyway.

And in my ~10 years of offroading, I’ve never had a big rock there. To get a big rock up in that area, how would it clear everything up under the truck ahead of that area?

That's what I was thinking. It'll be tucked up right behind the rear diff and crossmember. So I should be fine, but I was thinking that the crossmember is pretty much in line with where the wheels contact the ground. So if I'm on a big rock, straddling another tall pointy rock that could potentially clear the diff, then the wheels drop down off the big rock, the pointy one could maybe hit it. But that would be a pretty unlikely scenario I think. And a guy I work with just got a plasma cutter cnc and was planning on helping me make some armor for my gas tank and tranny, im sure I could bolt on a little skid plate over the tank if I wanted to be extra cautious.

Tank is supposed to arrive in a few days, I'll keep this thread updated!

 

[OverlandExpy]

Tank came, also had to buy a 3/16 push to connect fitting for it.


Decided to test it out, have a bunch of random fittings around my shop and a few spare pressure gauges, managed to make this:


Its got a little valve there I can close to take off the gauge, then open again to empty the tank. Used a power supply to power the compressor to not kill my battery, and just plugged the push to connect hose right into the tank! 10 amps was pretty weak though, and ran a lot better off the battery directly



Tank filled up to 20 PSI in under a minute, which for a 5 gallon tank was not half bad. A lot better than I was expecting. The issue came when I shut off the compressor, and noticed a leaking noise coming from the where the dryer is connected to the compressor, at the center of this image:



A small screw was holding the dryer on, so I took it off to inspect the attachment point



It looks to me like this little tapered part of the dryer just sits on the compressor, with nothing keeping it attached other than the pressure that one small screw is able to produce. Which is not much, as the dryer has a bit a play in it. I was able to press the dryer into the compressor with my hand, and that stopped the hissing.

So now I need to make a decision. Keep messing around with this thing, or just buy an onboard air compressor from ARB or VIAIR for 250 ish bucks. My concerns with continuing on with this project are keeping a high PSI in the system without the dryer leaking, all of those dinky little press to connect fittings/hoses, and the compressor itself which was used for 150k miles and a fair amount of towing, so the air suspension was definitely being used a lot. I don't want to go through all this effort of running lines just to have the compressor crap out on me in a year or two. But I guess if that happens I can just go to pick and pull and get a used one for cheap.

I like the size and location of the OEM compressor, but a compressor that can go to higher PSIs faster would be nice too. Although other ones are a lot bigger and I would need to find a good mounting location for it. Im not sure if I would be able to fix the leak in dryer though due to how the coupling is designed. Does not seem the least bit ideal for high pressure applications.

Wanted to get your guys' opinion on it, see if its worth keeping on with this. Havent spent much money on the project yet besides the tank, which I'll need regardless of which compressor I use, and one push to connect fitting. So I wouldnt be losing any money ditching this project, except for the expense of a new compressor.

 

[OverlandExpy]

Just in case anyone is following this thread or finding it sometime in the future, the stock compressor/fittings aren't meant to run more than about 50 psi. It won't work like a typical compressor that you would be able to run air tools/fill a 35in tire. I ended up buying an arb on board air compressor and will be installing that soon. I'll post future updates to my main "balls to the wall" thread with the rest of my mods.

This will probably be the last post on this thread, but if anyone needs a spare oem compressor that runs great, feel free to pm me. I'm never going back to the air ride suspension anyway.

 

[Vincent Vega]

Just in case anyone is following this thread or finding it sometime in the future, the stock compressor/fittings aren't meant to run more than about 50 psi. It won't work like a typical compressor that you would be able to run air tools/fill a 35in tire. I ended up buying an arb on board air compressor and will be installing that soon. I'll post future updates to my main "balls to the wall" thread with the rest of my mods.

This will probably be the last post on this thread, but if anyone needs a spare oem compressor that runs great, feel free to pm me. I'm never going back to the air ride suspension anyway.

Will a larger aftermarket compressor fit where the factory compressor is located? The aftermarket would probably have to be mounted without a tank due to lack of space I would think. My Exp does did not come w air suspension, and I have never opened up that interior trim in the rear (where the compressor would be) to see how much space is available.
I am considering which compressor to get for offroading, and before reading these threads I was leaning towards a portable compressor just because I could not find a good place to mount an on-board compressor. Now I am wondering if an aftermarket compressor could fit in there? Anyway you had a good project going there, sorry it didn't work out.

 

[OverlandExpy]

@Vincent Vega So the compressor I bought is the ARB ckma12 compressor. The OEM compressor and integrated mount is actually a fair amount larger than the arb. I could probably fit it under the windshield wiper fluid reservoir where the suspension compressor was, but it would be way more trouble than its worth since I'd have to fab up a custom mount, so I'm thinking I'm going to mount it how @Vancouver Bob bob did in his here. Looks like he has the same one that I bought. I figured that out of the engine bay would be better for it so it could get some cool air. Also I bought myself a light bar and some ditch lights for christmas and was planning on mounting the light bar behind the bumper on the frame, so I'll be removing the front bumper anyway. I'm planning on mounting my tank right behind the rear diff and crossmember where the spare would go. Plenty of room for it there. Right now me and my offroading buddies use a portable one. Its kind of a pain to pop the hood, take it out, set it up, and have to leave the truck running for 20 min while you air up though. With the 5 gallon tank, I'm hoping to slowly fill it while I'm on the trails, giving the compressor plenty of time to cool down between cycles to not wear it out. Get the tank to 100-120psi ish it should be enough to get my tires filled up most of the way and will minimize/eliminating idling time. This is the compressor I've been using when I hit the trails at the moment, it does its job but gets hot quick and takes a little while. But it'll fill up 4 35in tires no problem if you have some patience. Here is the one I was going to buy before I decided on the on-board arb system instead, heard good things about it and met a few people on the rubicon who used it and swore by it. If you're on the fence about which one you want to do, I'd just buy a cheap-ish but still decent portable one for ~$80, and if its too annoying to deal with, install an on board one and then you'll have a backup in case one ever fails!

 

[GONS]

The concern I would have- the air suspension compressor for the Expedition/ Navigator times out (***** down) after running for a designated amount of time as a protection against overheating the compressor motor. I speculate the compressor time out constraints greatly limits what the OEM compressor can be used for outside of filling air springs.

 

[Vincent Vega]

@Vincent Vega So the compressor I bought is the ARB ckma12 compressor. The OEM compressor and integrated mount is actually a fair amount larger than the arb. I could probably fit it under the windshield wiper fluid reservoir where the suspension compressor was, but it would be way more trouble than its worth since I'd have to fab up a custom mount, so I'm thinking I'm going to mount it how @Vancouver Bob bob did in his here. Looks like he has the same one that I bought. I figured that out of the engine bay would be better for it so it could get some cool air. Also I bought myself a light bar and some ditch lights for christmas and was planning on mounting the light bar behind the bumper on the frame, so I'll be removing the front bumper anyway. I'm planning on mounting my tank right behind the rear diff and crossmember where the spare would go. Plenty of room for it there. Right now me and my offroading buddies use a portable one. Its kind of a pain to pop the hood, take it out, set it up, and have to leave the truck running for 20 min while you air up though. With the 5 gallon tank, I'm hoping to slowly fill it while I'm on the trails, giving the compressor plenty of time to cool down between cycles to not wear it out. Get the tank to 100-120psi ish it should be enough to get my tires filled up most of the way and will minimize/eliminating idling time. This is the compressor I've been using when I hit the trails at the moment, it does its job but gets hot quick and takes a little while. But it'll fill up 4 35in tires no problem if you have some patience. Here is the one I was going to buy before I decided on the on-board arb system instead, heard good things about it and met a few people on the rubicon who used it and swore by it. If you're on the fence about which one you want to do, I'd just buy a cheap-ish but still decent portable one for ~$80, and if its too annoying to deal with, install an on board one and then you'll have a backup in case one ever fails!

@OverlandExpy I agree, the @Vancouver Bob setup is cool. The only thing is I can't figure out from his photo is whether the grille will still fit on there. Also have you seen this ARB deal on Amazon that includes a mounting bracket? I don't know if the mounting bracket would help our application, seems like you would need to order it and play around with it to see if it would work (if you have a Jeep it probably bolts right in, ha ha). If not you are back to having to build custom mounts.

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