Tag Archives: On Board Air / O.B.A.

On board Air using a York Compressor

By: Muddytazz

On board Air using a York Compressor

Article and photo’s by Jeff Rice

What typically is one of the first things that off roaders do when they hit the trail? They air down their tires for better traction. That’s the easy part, but what about airing them back up? There are several options to accomplish this, but I’m going to show you what I did.

Here are a few options:


  • Bring along a portable air tank.That should give you enough air for a couple refills, but won’t do you any good if your going to be out on the trail for a while and have no way to put air back into the air tank.

  • Carry a small 12volt compressor that plugs into your cigarette lighter. It’s very useful for emergency refills, but tank way to long to refill large tires. There are some companies out there that sell portable air compressors that are designed to fill up tires fast, but the majority of those won’t run any air tools and they are typically well into the couple hundred dollar bracket.

  • CO2 tanks. These are a lot better than the smaller portable air tanks, will generally fill a lot of tires, and will run air tools. The only drawback is you have to get them refilled when they become empty. Plus some can cost more than the portable air compressors.

  • Run a compressor off of your engine. The will supply a large amount of air, is plenty fast enough to run air tools, and will always work as long as your engine is running. Plus the compressor itself is fairly inexpensive. But, some sort of bracket might have to be fabricated to mount the compressor to the engine because there are so many different accessory and belt configurations available for all the types of vehicles that are out there.


Out of these four options, I chose to go with a compressor that is driven off of my engine. The cost of parts and materials as well as the constant supply of air were my benefiting factors. The most typical style of compressor use for this type of setup is the York Compressor. Which could be found on Ford, Volvo, AMC, IH, and Oldsmobile vehicles from the late 70′s to the early 80′s?

Why use the York? The compressors that were found on most of these vehicles with A/C were internally lubricated by the Freon in the system. To pump air, you would need to have an external oiler to keep the compressor lubricated, and an output filter to remove the oil. This is not necessary with a York compressor as it has its own internal reservoir for oiling making it a better choice for pumping air. However, there are some variables you need to know about when considering which style of York to use. There are three different strokes available, as well as many different types of hose connections.

Out of the vehicles that used York, the long stroke version is most commonly found in Volvo’s from the late 70′s to the early 80′s The hose connections can also be a clearance factor when looking for the right compressor to be able to fit under your hood(if your limited to space). Volvo and AMC hose connections run horizontally across the top of the York, while Ford hose connections stick straight up out of the top of the York and then connect to the A/C system. This can be a problem if you’re limited to engine compartment space. Although the different connector styles are interchangeable, but be careful, finding fittings for the factory A/C connectors can be difficult because the threads on the York connections don’t match common pipe fittings. Fortunately, onboardair.com makes custom flange fittings that use a common 1/2″npt, and they are a direct bolt-on replacement for the factory fittings.

The compressor that I found and used was out of a 1979 Volvo, and had the flange style fittings. Now, there are also several different variations of pulley/clutch assemblies found on the York’s. After deciding on which model I should get, I called a dealership to find out how much a brand new York was going to cost. After making a few phone calls, the general price range for new was $200 – $300, so I decided to get a used one instead. I was able to pick mine up from the local wrecking yard for $25. It may be a pain to get out depending on the vehicle. Just make sure that before you buy the York, test it in the wrecking yard to make sure it works.

There are two things that you need to test for:

1 – To see if the clutch is going to work and 2-If the York is going to pump air.

To test the clutch, look for the wire that is coming out of the backside of the clutch. Ground the compressor (obviously to something metal) and touch the wire to a positive battery terminal. You should hear a “CLICK” when you apply power to the wire. This CLICK is the outer part of the pulley locking to the inner part on the crankshaft. You should be able to turn the pulley with it locked and be able to hear air being pumped. It should also be harder to turn. Also, when you remove the wire, you should hear a CLICK again, and the outer part of the pulley should disengage and spin freely again. It is also a good idea to plug one of the top-side hose connections with your thumb and turn the crankshaft (inner part of the pulley) with or without the clutch being engaged. Depending on which direction it’s turned, it should either suck or blow air against your thumb. It’s a good idea to turn it both ways just to be sure it works. If the compressor fails either of these two tests, it has internal damage, or a bad clutch. New clutches aren’t cheap, so be sure to get one that works.

How did I mount my York?

This is probably the most complicated part of the whole project. For the older style Chevy owners, there are no such manufactured brackets available. But for the newer rigs such as Jeep, newer Chevy’s and newer Dodge’s, there are brackets available from onboardair.com. So for my application, I had to make one. I made my own adjustable mount out of 1/4″ steel plate. I had no intension of keeping the factory A/C, so I removed that and planned for mounting the York in its place. I also had a spare slot on the pulley from the water pump and power-steering pump from the removal of the stock A/C to be able to run the York. If your engine uses serpentine belts, onboardair.com also has a serpentine/v-belt combination pulley for alternators that will allow you to run a v-belt to the compressor.

York mounting bracket that I made to fit a 73-87 Chevy:

Make sure you keep the York lubricated or you could possibly burn it up. Remember, it was used to pumping Freon all its life and now its using oil, so you have to keep it supplied with oil. The York has an oil fill hole on both sides of the compressor body. The York only has a 12 oz. total capacity and depending on how you mount it (vertically or horizontally) will depend on how much oil is actually inside the York. To measure the oil, you’ll have to come up with a dipstick of some sorts. You can make your own out of a coat hanger, or buy one from onboardair.com. I chose to just buy one since it was only $5.00, but if you want to make your own, here is a link to how to make one compliments of Ben Hollingsworths: CLICK HERE.

Now that the York is not using Freon anymore, it uses standard 10W-30 motor oil. After I bench checked the fluid, I got to install the York and all of the components to complete my project. The flange fittings for the intake and output ports on the York came from onboardair.com. Their fittings make setting up the air hoses much easier because the threads are a standard size, and most of the fittings I needed could be found at a local hardware store. For the intake filter, I used an exhaust muffler. It’s compact and mounts directly to the flange fitting. For the output side and the rest of the system, I used standard RED 300 psi rated, 3/8″ air hose. The line from the compressor runs into a one way valve, to stop air from coming back into the compressor, when it shuts off. The ON/OFF switch for the York, the relay to run the power through and the extra fuse box I installed were all installed first. I also used indicator lights on the top part of my dash so that I can see if the switches are in the ON position.

After I got done running all the wiring, I proceeded to make my own manifold. I went this route because I had some aluminum lying around. You can make your own or you can purchase one from onboardair.com. After the manifold was made and painted, I installed the pressure switch, pop-off valve, and gauge and pressure regulator. The found a nice spot on my inner fender well to mount this all too. Then I wired in the pressure switch. A pressure switch is necessary to control the compressor. It turns on the compressor when the pressure drops below 90-95 psi and turns it off when it reaches 125 psi. This keeps it from running constantly and setting off the safety valve. The pressure switch is a SquareD pressure switch. It comes with or without an unloader. I choose the one without the unloader. Here’s a link to the catalog on the SquareD website for their pressure switches: CLICK HERE.

Having an air tank for storage is essential if you plan on running air tools, and it makes for faster fills on tires. There are a few companies that sell small air tanks that are rated for high pressure (up to 150 psi.) for around $60 or $70. Small air tanks are also common on large trucks that have air brakes. Last but not least was to mount my air tanks and run the lines. I went with 2, 5 gallon tanks that I happen to find a good deal on eBay. My tanks actually are 8 port low rider air tanks. I only needed 2 of the 8 ports, 1 for the inlet and 1 for the outlet. Looking for a place to mount tank(s) can be a trying task. Luckily with a suburban, there are lots of choices. With having two air tanks though, I was trying to find someplace that was balanced. I managed to mount one tank on each side of the body underneath between the frame rail and my rock sliders. Later on as things go along, I’ll end up skinning that section to protect the air tanks.

I ran them a bit differently than most people do though. Typically what people will do is run a line from the manifold to one tank then jump over to the other tank then out the second tank with an output to the front and rear of the vehicle. Well, the way I ran it was I ran off the manifold to a t-fitting, and then ran separate lines to each tank. So in a since, the tank I have mounted on the drivers side is plumped to the front bumper and the tank I have mounted on the passenger side is plumped to the rear bumper.

How the complete system works.

In my eye, it works perfect! This had to of been the cheapest, and biggest bang-for-the-buck modifications I have done to my suburban. I have around $125 invested in it, and I don’t ever have to spend another dime on it. I decided to run some tests to see how fast it would fill tires and if it could really run air tools. My first test was to air down a 33″ Swamper TSL to 8 psi, then fill it back up to 35psi. The total time on the fill was about 50 seconds. Tank fill time is just under 50 seconds, way faster than most portable compressors that I’ve come across. The compressor pumps air faster or slower depending on the speed of the engine. Mostly when in use, the suburban is at idle (700-800 RPM). It’s not recommended to run the compressor over 1200-1300 RPM’s for a long period of time. I then grabbed my impact and proceeded to remove all eight of lug nuts on my rear wheel without a hitch, never having to stop to let the compressor fill the tank back up. It can also supply enough air to run grinders and ratchets, probably not as well as a 60 gallon 2 stage compressor, but good enough to make emergency trail repairs.

Maybe later on down the road I might install a hand throttle so I can control the throttle from within the engine compartment instead of having someone else sit on the gas pedal to bump the idle up for an extra boost of power.

Now it’s off to my next project. On board Welder.

Parts used on this project:

Part – Dealer – Part number

Square D pressure switch…. Grainger ….. 5b419
Intake filter muffler….. Grainger …..1A328
Gauge….. Grainger….. 5wz22
On-way valve …..Grainger ……5a705
Safety valve …..Grainger …..5a709
Misc Brass Air fittings ……Napa ……Parts bins
300psi 3/8″ air hose ……Napa …….Off the shelf

York Install in a Full Size GM for $100

By: cbbr

We must have looked at 400 vehicles before we found what we were looking for a York A/C compressor. It was in a 1970′s Ford F-100. It did not have an identification plate, but the York is immediately recognizable. Check it out -

We cut the v-belts and spun the compressor. It spun free. Next we cut the hoses as far from the compressor as possible and spun the compressor while pushing the clutch in. Suction was good.

We removed the compressor and the stock brackets just in case we needed those (again, more on those later). We took the compressor and some assorted junk that we couldn’t live without to the front and hooked the compressor to a battery that they have for testing purposes. With the negative from the batter connected to the body of the York, we touched the positive to the battery and the clutch engaged.

$24.95 (plus tax) later and the York was in the back of the Suburban. I paid another $10 for the factory bracket which was a waste of money.

I had moved the washer fluid container forward in hopes of installing on board air and a tank. That in mind, we were working on an install on the driver’s side. We took a section of 90-degree angle steel and “fabricated” a bracket. Truth is that we cut it, drilled holes in it and trimmed it with a grinder until it fit on two studs coming from the block at the manifold. We then took a piece of flat bar, bent it to 90 degrees and attached it to the side of the York and to the top drivers side bracket bolt holding the alternator. Looks like this -

Next came the pulley. I have basic welding skills (basic is being kind) and a MIG, so we intended on using the idler pulley from the bracket that I bought as the drive pulley for the York. Specifically, the pan was to weld the alternator pulley and the idler pulley together so that the York would be driven off of the alternator.

About a hour later we were off to AutoZone where I learned two things – 1) you cant just buy an alternator pulley if you screw yours up and 2) the idler pulley that we had just destroyed trying to remove it with a BFH was $15.

These facts made us reconsider my original plan. A call to www.OnBoardAir.com was in order. I spoke with the folks at OBA who were very helpful and a few days later the pulley was at my doorstep. I costs $40 and was well worth it. I also ordered a dipstick from OBA for $5, which seemed like a good idea.

The OBA pulley (I got the underdrive model) works great. I measured the belt length with a piece of string and got a v-belt from AutoZone (just go around the counter and try them out), hooked it up and now have OBA.

Next was how to harness the OBA and make it more useful.

I had a cheap, broken 6 ½ gallon home compressor in the pile on the carport which fit the bill. It was intact, but didn’t work. I took off the engine, we cut off the handle and wheels (being careful to stay off of the tank with the cutting wheel) and the tank fit perfectly in the area left after moving the washer tank. The tank -

Wiring was simple. Fused hot wire from the battery to the pressure switch and fused hot wire from the pressure switch to the lead on the York (25 amp each). The tanks pressure switch also has a two position switch for when the compressor neds to be totally off. The York grounds to the Suburban and only has one wire, so its hard to mess this up.

As for plumbing the system, that’s where the stock hoses came in handy. $20 worth of “fix-it” kit and couplings later and the system was plumed. I used the stock outlet hose to make a short compressor hose, used an extension and connected it directly to the tank. See -

For the inlet, I attached a silencer from a lawnmower (costs $3 at Home Depot) into the stock hose with a “fix-it” kit that is for hot water heater hose ($5 at Home Depot). See -

I attached the tank with two ratchet straps (costs $10) that are bolted to the inner fender well. I used a piece of insulation to keep the bolts from gouging the tank. See-

After testing the switch and trying a few combinations, the tanks pressure switch operated the York’s clutch perfectly. I set the switch to turn the York on at 75 lbs and off at 125. There are two safety valves – the original on the tank and another that I attached to the tank at the inlet using a 4 way connactor from Harbor Frieght.

The quick connect from the tank is zip-tied to the grill and I put a waterproof switch in the grill so I don’t have to raise the hood to use the OBA.

Tools run off of it with no problem and it should be great for airing up. All for about $100 and one day of “work”.