Grab the next window ac unit you see and take out the compressor, braze fittings on the ends (whatever size you need) And you got yourself a high pressure compressor on one side(I got 160psi out of a 18 year old one), and a vacum pump on the other side for vacing down ac systems or what ever you want to do with it!! Just dump some oil in every now and then and connect the ends to let it circulate for a few minutes!! You could pipe to a tank and all that
but I don't want to get into all the wiring so I just chuck it up and let her pump!

 

It will certainly work. My first compressor many, many years ago was an old A/C compressor but I don't know that I'd want all of that residual oil in my compressed air. If you just need to blow things off I guess it would be OK but I wouldn't want oily air in my tires and you certainly can't paint with it. Without a tank for volume, you can't operate air tools either.

 

Not to mention the compressor circulates the oil through the system, and without the closed system it will burn up before too long.

 

actually if it's an old one it will survive a long time if oiled often. Slap an automotive AC clutch on it and install it under your hood with an auxilary 10 gallon tank and you have yourself on-board air. The older home AC compressors are generally much better for this purpose than the automotive AC compressors most people use. Auto ones are used in vehicles as air compressors simply because the bracketry usually exists for a given engine.

For on the road air, a little oil in the lines isn't bad. It's not like you're going to be painting your truck while idling anyway. But the larger, home AC compressor units can drive a 3/4 impact gun making removal of lugnuts that much easier.

 

If you're going to use an automotive a/c compressor, use a York. They are a twin piston design, have oil in a sump internally, and do not need any external oil source. They also put far less oil into the air supply. The more modern radial piston designs don't have a sump, and rely on oil being blown through the system. Very temperamental when used with air.

 

They last a lot longer than you think!! Like I said I connect the ends together and let it circulate oil for a while so it gets on every surface!! (marvel air tool oil) If you are worried you could put a air oil seperator. but it's not a bad thing really. Of course a tank would catch some too, I haven't had the need for a tank (air tools make you weak) and it will blast out spark plug holes, etc. I am just putting up an option for guys with more time than money!! Plus it's the cheapest vac pump you can find!!!

 

I don't know how you would do that. A compressor from a window A/C unit is a hermetic compressor. The 115 or 220 volt motor and compressor are contained inside a sealed steel cylinder. In addition, the motor is designed to be cooled by the returning refrigerant. It won't last too long without the cooling. If you're determined to use an old A/C compressor for on board air then an old automotive piston type is the way to go but by the time you finish building brackets, finding a mounting location and wiring up the clutch you probably could just have bought a unit made for automotive use.

 

Too bad it won't pull a good enough vacuum on a A/C refrigerant circuit, it is a waste of time.

 

Have you tried one crash? The smaller the better for pulling a vac!!

 

I haven't picked up a curbside AC unit in ages. The last one I nabbed was a massive dinosaur and the motor drove the compressor (and cooling fan) with a v-belt, so that's where my suggestion of installing it in a vehicle seems reasonable to me.

If the newer ones have the motor and the compressor in the same housing, sharing a common shaft then it becomes much more complicated to seperate the two and ditch the motor for in-vehicle use, I'd agree. But even that's not a big deal, just more time and effort. I could think of several ways of the top of my head to shave off the motor leaving just the compressor. My 12x24" lathe comes to mind

Anyway, as someone else suggested, an old York compressor would do the trick then and making bracketry isn't a big deal - mild steel is fine, even scraps left over from other projects. Don't you save scraps?

There is nothing wrong with buying something "off the shelf" and bolting it on and immediately enjoying it. I prefer the cheaper, more time consuming method of fabrication where possible. If an on-board air kit was $150, then yes, I wouldn't bother spending about that in cobbled together junkyard parts, or the time involved.

If I can save $350 (or whatever) by cobbling, I'll cobble.

This is the same reason why I'm almost ready to start fabricating a "kneeling" rear air suspension for my crewcab. Instead of spending about $2500 for a bolt-on kit, mine homemade equiv will cost me about $400.

And yeah, my truck will be on jackstands much longer than if I purchased and slapped on a kit specifically designed for my truck. Absolutely.

 

get some tractor trailer air bags, And rig up a lever system with them to compress the regular springs kind of like traction bars pivoted in the middle with the airbags on the other side of the pivot, fill up the air bags and they will compress the springs dropping the rear end! Look into air axles on a Mack dump truck they hardly have any leverage at all and it lifts up the trailling arms, the axle and two 22" tires some guys run super singles on them that is a heavy tire!!! I use Co2 for on board air since I found two tanks in the trash full!! It works good to cool down your truck on a hot day too!!

 

Due to the design of the compressor, they are incapable of reaching a proper 500 micron or less vacuum.
I don't need to try one, I own a vacuum pump.

 

the best thing to use for an on board air compressor, if your going to try and build it yourself is an old york ac compresser off of an old wagoneer or somthing like that. its already got a double v pully, an electic clutch. all you have to do is get a pressure switch 90 on 120 off a 150 safety valve. a couple of adapter fittings to fit the lines in and out, and get yourself a small 2.5gl or so air tank from a truck junk yard. mount the compressor with the intake and outlet on top since the unit has a self contained oiling system you dont really have to worry much about oil in the air. there are plenty of places on line to find out a decent way to rig this system up. and it will fill a set of 35.13.5 15s pretty dang quick it ran my 1\2 in air gun pretty good on just eh compressoer alone.