OBA for the Financially Challenged

when i bought my last cherokee, i noticed that the air conditioning was unhooked and it didnt even have the stock a/c fan (existing fan was duct taped around to seal it...)

however the ac compressor was still there. so i clipped the wire and stripped a little. touched it to the positive on the battery and presto the clutch kicked in and it blew air (and oil) all over me.

if your a/c compressor doesnt work you can either stop here or go junkyarding.

next i unhooked the rubber hoses from the two fittings on the top of the compressor so i could figure out how to plumb it.

hardware store time!
i went to the hardware store with my fittings and spent 35 dollars on
20 ft pre made air hose,
2 ft of 250psi hosed*******had to have a compression fitting hose made later*******
1, 1/4 inch brass T
1, 1/4 inch brass nipple (male on both ends)
2, 1/4 inch brass barb nipples
1, 1 inch to 3/4 inch reducer (black steel)
2, 3/4 inch to 1/4 inch reducer (black steel)
1/4 brass female air chuck fitting
Free old fire extinguisher (one that will fit under your hood or whereever you want to mount it) *********later removed this but might add it again*********

one of the 3/4 to 1/4 fittings may depend on what size inlet your fire extinguisher has, you need to completely empty the fire extinguisher and unscrew the entire assembly off the top of it using a vice and a strap wrench.
take your fire extinguisher with you and find an appropriate reducer that will fit nicely inside (chances are you will not find the appropriate thread, it will need to be welded)

now buying these things will get you going. however your inlet air will not be filtered and you will not have an air pressure guage, or pressure switch (i am without switch so far also)

here is where the fabrication work comes in.

take your fitting for the extinguisher and put it inside the opening of it. make sure you have something to plug the 1/4 inch hole with. a steel pipe plug would be the best but anything will do as long as its not flamable.



with fitting in opening, tack weld 4 sides of the fitting so it will not distort, once tacked, lay a nice uniform bead around fitting. this may or may not leak air. i got lucky and had no leakes from this part however i have small leakes elsewhere. leakes are not critical, as they will be very minimal and only an issue if you wanted to hold air pressure for a length of time. (it would probably take my system 5 or 6 hours to bleed off from 180 psi.)

after the fitting is welded in you can teflon tape the 1/4 inch nipple on both ends and assemble the brass T and the extinguisher simultaneously. one of the other openings will be used for the 1/4 brass barb nipple. attach the T so you can recieve air from the pump and run air to your air hose whichever way would be best for you. you will see which way i ran mine from the pictures i post later.

next put the 1 inch to 3/4 reducer over the threaded end of the larger of the two a/c fittings. leave enough room to screw the 3/4 to 1/4 fitting in it. you may leave it in while welding just to make sure. but dont teflon tape it yet.



before welding make sure the O-ring is out of the stock fitting. this will be replaced after fitting is cooled.

weld reducer onto stock fitting, there really isnt a way to check leaks here untill the unit is completely assembled. if you suspect a leak or just want to weld up any possible culprit or orfices feel free to do so as the only openings you will use are the welded one and the stock attatchment to the compressor.

after this is completed you can teflon tape the 3/4 to 1/4 reducer and 1 of the brass barb nipples and put in the 1/4 inch hole of the reducer. replace the o-ring and tighten back onto the passenger side hole of the compressor, this is your outlet. DO NOT OVER TIGHTEN!!!



under my cherokeehood there isnt a lot of room so i just have the air tank laying right next to the fender ontop of some wires and such between the battery and the water resevoir.

run the short peace of hose between the barb nipples on the compressor and the T from the air tank and hose clamp them. use the last opening of the T on the tank for your air hose. then on the other end, tighten your air chuck fitting on.

at this point you are now able to test your air.

put some sort of air tool or an air blow gun in the hose as to not over load the system

start the jeep

touch the wire to the battery and presto. you should be pumping air, you can play with the air by letting it pump up a while and then using the blow gun to see how fast it pumps up.

Freebies:
old heater hose
old water pump nipple (small block chevy)
old T i stole from my dad
old 1/4 nipple male on both ends.
old air guage i stole from my dad
old toggle switch i stole from...dad...

misc...something that will fasten nipple to airbox, couple washers for airbox if needed (big 7/8 washers) hose clamps


in my application the air guage needs to be small to clear when the hood is shut.

make sure all air is out of system. then unsrew air hose from brass T. use nipple to attatch T's together put hose in one outlet and guage in the other.

you can run the switch anywhere you want. im not gonna hold your hand through this one! hah!

the heater hose i clamped onto the inlet for the compressor and ran back to, and along the firewall and then back up to the air box. i drilled a hole in the air box (on the filtered air side) and attach the water pump nipple to it, then hose clamp the heater hose to the nipple. now your air is filtered. and the a/c compressor is much much quieter.********i have since removed air box and just put a chrome oil breather in the end of the hose*********

the only other thing i advise is some sort of oiling i havent quite figured that out yet but as soon as i do i will post here. ********see picture********



i also stick a small screw driver in the throttle linkage to bump the idle up while running the compressor. ********not too much or you'll drastically reduce the lifespan of your compressor*******

eventually i want to get a pressure switch but checking on a 175 psi switch would have run me 399.99...i said no thanks. i can get a 125 psi switch at the hardware store for another 35 bucks. *******have one....got it for free....scored*******

i deflated one of my tires completely and pumped it up to 35 psi in 15-20 seconds. small tires 30's but none the less quick. with the compressor running and filling up the tire the system ran at an impressive 120psi.
running an air grinder takes it down to about 25 however.

anyhow have fun with your budget onboard air. unfortunately a big part of this is being able to weld or knowing someone that can. if you do then you are set.

You should install a cooler just after the compressor.


One of the locals drilled a hole in the cap at the top of the compressor, and put a grease fitting in it. He pop's one squirt of grease in before every big event.

x2, some sort of oiler.

Also, pics don't work, but nice write-up.

-----Matt-----

fyi a/c pumps will put out up to 200 psi, you just need to find a tank that will support the pressure. i used to run a sanden ac pump on my mini truck with air ride, works for about a month of lots of every day use, just dump a little oil down the inlet tube every once in a while. fills an 8 gallon tank in about 2 or 3 minutes.and i filled it about 20 times a day lol, there is a better compressor to use but i cant remember the name of it, i upgraded to it, but cant remember the name.

GEOSHITTIES STRIKES AGAIN!!!!!

i do have an oiler that is inline before the compressor.

the thing runs like a top, i dont really rev the engine any more to make it fill faster because no matter how fast its spinning the oiller still puts out the same amount.

i'll see if i can host these somewhere else that doesnt have a data transfer limit so ridiculously low.


and FYI the good compressors are the YORK's

Email me the photos and I'll host them for you.

[email protected]

The pics are showing uip fine for me. good write up too!

email sent

hosted, sent you the url.

Right on. Thanks for the write up. I'm going to start scavenger hunting the barns for parts.:farmer:

if the pictures fail to show up again.

here's a seperate host compliments of Cal

Looks like a good clean install. Nice work. I would love to do this but I love my AC more. You planning to keep that coil of hose in there? Maybe a quick disco coil air hose in the future?

nope

thats the perfect spot for that hose and i'm guaranteed always to have it with me.

enough to reach all four tires.


i didnt do a disco-hose on purpose

you going to mount a tank up?

had one that i took off.

i'm thinkin about putting it back on. the only thing the tank really does though is make the compressor run longer.

its not big enough to fill a tire a significant amount before it kicks on but it takes longer to fill the tank so it puts more stress on the compressor.

it did somewhat serve as a separator though the way i had it mounted so i'm thinking of putting it back on.

i'm going to powder coat it blue like my valve cover though.

my battery hold down will also get the same treatment

Nice job!

If your going on the TSF run I'm going to have to check it out. I was looking at getting a CO2 setup, but a 20lb bottle at the local shops goes for $100+ not even including a reg. I'm running 30's as well and I like the sound of those times, 20 sec . I might have to start gathering parts.

Does the outlet hose coming off the compressor get hot at all? I remember reading a thread where the person had to run copper tubing off the outlet for a foot or so (rubber hose melted).

Very nice write up i am gonna probaly go this route if my ac fails

TORX said:

Nice job!

If your going on the TSF run I'm going to have to check it out. I was looking at getting a CO2 setup, but a 20lb bottle at the local shops goes for $100+ not even including a reg. I'm running 30's as well and I like the sound of those times, 20 sec . I might have to start gathering parts.

Does the outlet hose coming off the compressor get hot at all? I remember reading a thread where the person had to run copper tubing off the outlet for a foot or so (rubber hose melted).

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i used to run 30's but now either 31's or 33's, and when it filled in 20 seconds the engine was revved up. it does fill fast still but i strongly recommend you DONT rev the engine. its not a race to fill your tires and you decrease the lifespan of your compressor.

and the rubber hose i used to have did get hot and soft and would blow off the barb fitting so i had this black one made with INV Flare fittings on it. its high pressure hose too, this is one route you'll have to take. a rubber hose with hose clamps just wont work unless you take breaks while filling.

the high pressure hose and fittings crimped and ready to go was less than 20 bucks IIRC

WVUwheeler said:

Very nice write up i am gonna probaly go this route if my ac fails

Click to expand...

it depends on why your ac fails. if it's the compressor then you'll have to get a new one and if you get a new one then your ac will work again also.

its a committment and i did it because i dont really regard a/c as a trail need and when i bought my jeep most of the required ac parts were missing.

if your system starts to leak freon or something like that and you dont want to keep paying to fix it and fill it, that would be a worthy reason to convert

Hey Wingnutooa do you get any oil in your air lines and or tires from the inline oiler? I am just concerned what the oil would do to the rubber. Any more info would be greatly appriciated. Oh what size fire extingisher tank did you end up using?

If you have a truck yard (semi truck) close the air tanks can be picked up cheap there also. If you can find a bus in a yard or anything with air brakes. The lines also can be pulled and the fittings. If you can find one truck there is enough tubing there to do a few rigs. I got lucky and found a 1000' spool of air brake tubing on ebay a few years ago for a great price so I have been using that for the compressors that I have installed and sold on the side.
Great Job!!! Much easier than moving your battery and installing a york and a lot better than a 12v.