A close-up of the wiring harness and switches.

For my installation I wanted to do a "full pneumatic" system - that is, a system where there are no solenoids used, everything downstream of the compressor is pneumatic only, and the only electrical part of the system is the power to run the compressor.

More on this later - for now, the important thing to note is that the supplied wiring harness, as seen at left, comes in 2 parts and will have to be modified if not following the ARB electro-pneumatic route. To help keep things clear, I call the larger portion of the harness (at the top of this pic) the "compressor harness" and the smaller section the "switch harness" (where 'switch' refers to the compressor activation switch).

The dash-mounted, compressor activation switch (left) and the compressor's pressure switch.

The compressor activation switch is used to turn the compressor on or off and is used in both electro-pneumatic installations as well as full pneumatic systems.

The pressure switch installs in the compressor's small tank and, with the dash mount switch on, automatically switches the compressor on when the tank pressure falls below 70psi and switches it off when the pressure reaches 100psi.

One of the coolest features of the compressor is the fact that you have 270° of freedom in choosing how to rotate the compressor in its mount.

By loosening the two small hex-head motor mount screws (red arrows) you can loosen the mount and rotate the compressor in the mount anywhere from 90° to the left, through vertical, to 90° to the right.

Here the compressor is rotated about 45° to the right in its mount.

Unpack the kit and lay it all out on a clean work surface.

Remove the caps from the pressure switch and wrap the threads with teflon tape.

Apply teflon tape to the threads of the air filter, remove the red rubber plug in the end of the compressor, and thread in the air filter.

Note that you can also thread in a 1/4" NPT hose barb and use a length of tubing to relocate the air filter to a more suitable location. This can be useful should, for example, you choose to mount the compressor in a hot, dirty engine bay. The ARB manual contains details on max allowable lengths for different diameters of tube.

This diagram, from the ARB manual, illustrates the wiring for the compressor. The portions highlighted in red are those that you need to retain for a full pneumatic installation. Note that the "Firewall Port Disconnection Plug" is the place where the "switch harness" (upper part of the diagram) connects to the "compressor harness" (lower part of the diagram).

To modify the harness as shown, you essentially just cut off the unneeded parts - those that connect to the solenoids and the ARB dash-mount locker-activation switches.

The modified switch harness looks like this

To modify the compressor harness, cut off the 2 solenoid connectors (circled in red) as they will not be needed.

This diagram shows a typical directional control valve.

Air pressure is supplied to the Pressure Passage.

Depending on the position of the sliding spool this airflow is either connected to Passage A while Passage B is connected to the Exhaust Passage, or the airflow is connected to Passage B while Passage A is connected to exhaust.

Directional control valve's are normally classified according to the number of possible flow paths or "ways" they have.

The simplest example is a 2-way control valve.

Obviously, this type of valve has only 2 possible paths - flow path open or flow path closed. In other words - "on" or "off".

This diagram illustrates a 2-way valve and shows the ANSI symbols for each of the valve's positions.

Often, in describing a directional control valve, we also include the number of positions the actuator has. This simple valve illustrated at left would be described as a "2-way, 2 position" valve.

What we need is a 3-way, 2-position valve. A 3-way, 2-position valve will alternately pressurize or exhaust a single port. In the case of our ARB - when the actuator is in one position, pressure is supplied to the port and the locker locks and remains locked. When the actuator is moved to the other position, the air pressure supply is blocked, and the port is vented to exhaust, allowing the locker to unlock.

The figure at left illustrates a 3-way, 2-position valve, with the accompanying symbols. In our installation, the port labelled"P" would be where we connect the air supply line from the compressor/air source, the port "A" would be where we connect the air line running to the locker, and the port "Ex" would be the exhaust port.

As for the symbols, note that a blocked port is represented by a "T" symbol, and that airflow between ports is represented by an arrow showing the direction of flow.

Knowing this, we can see that the position on the left of this diagram would be "locker unlocked" (pressure port blocked, line from locker exhausted) and the position on the right would be "locked" (pressure supplied to the locker line and the exhaust port blocked).

When browsing a catalogue of pneumatic valves or switches we see that the type of switch is illustrated using the ANSI symbols we have seen.

A typical switch may look something like this.

A 2-position switch would have 2 boxes.

A 3-position switch would have 3 boxes.

Recall our original example of the simplest on/off valve. Its diagram would look like this.

Note that in the diagram the ports may or may not be indicated by tick-marks outside the box and the ports may or may not be labelled or numbered.

All three of these diagrams illustrate the same thing - a simple 2-way, 2-position switch.

In this position, both ports are blocked, no air flows, and the switch is "Off".

In this position, the two ports are connected, the air flows in the direction indicated - from port 1 to port 2 - and the switch is "On".

In this example, the symbol on the far left represents a spring, and the symbol on the right represents a push button.

It's a spring-loaded push-button switch.

It has two boxes - so we know it's a 2-position switch.

Obviously, in one position the button has control (when it has been pushed), and in the other position the spring would have control (when it's extended).

With the button pushed, the spring compresses, and the flow paths will be those illustrated in the box next to the button symbol.

With the button released, the spring extends, and the flow paths will be those illustrated in the box next to the spring symbol.

This chart shows common types of actuators you might see.

Note that, even for a multi-position switch there may be only one actuator drawn if that type of actuator is capable of controlling a number of different positions. The most common type of actuator of this sort would be the lever (or joystick) actuated valve - much like a multi-position hydraulic valve (as seen on tow trucks, etc.). In this case, only the single symbol for the lever is shown.

At left are a picture of just such a valve and its ANSI diagram.

Q: For bonus marks, what type of switch is this? You should be able to tell by now from reading the diagram.

A: It's a 5-way, 2-position lever control valve!

Here's the diagram for a spring-loaded, push-button, 3-way, 2-position directional control valve.

Quiz:

Assuming the ports are labelled P for air pressure supply, L for line to locker, and E for exhaust, would you push the button in to lock the locker or release it to lock the locker?

Answer: Push it in. Because to lock, we want to connect P to L and block E. We can see this is the case in the box next to the button - therefore we push the button to lock.

This is the page from the catalogue of my local supplier (Princess Auto) illustrating the valve I chose to control my rear ARB.

The reason it is a 5-way is because I have a different brand of air locker in my front axle (that requires a 5-way switch due to different operation) and I wanted the two switches to match.

It's not a problem as I can simply block the unneeded ports in the switch that controls the ARB.

This side of the valve has the two ports illustrated on the top of the ANSI box diagrams.

They are labelled A and B.

If you look carefully you can see the sliding spool through the ports.

This side has the three ports illustrated on the bottom of the box diagrams.

They are labelled R1, P, and R2.

Showing the fittings used.

Top two are simply brass 1/4" NPT plugs to block off unneeded ports.

Two on left are 1/4" NPT to 1/4" compression fitting. 1/4" compression fittings connect to 1/4" SAE air-brake plastic hose that connects to the compressor (middle fitting) and runs to an exhaust (bottom fitting). You want to run an exhaust line because just leaving the port open would allow dirt into the valve which would damage the sliding spool and internal seal surfaces.

Right middle fitting is a 1/4" NPT to 3/16" compression for connecting to the rear ARB locker. With a bit of effort you can get a 3/16" compression fitting over the 5mm ARB supplied blue air line.

As I mentioned, I wanted 2 matching pneumatic switches to control two different air lockers.

Here they are laid out on the "centre console" (such as it is) of the buggy.

The one on the left, with the stick to the front, controls the front (non-ARB) air locker.

The one on the right controls the rear ARB.

The air flow through the ARB switch is indicated in the picture.

Note that the 2 switches share the incoming air supply from the CKSA12 via a T fitting. There's a reason for this...see below.

Another view of the valves.

Notice that they are bulky and with all the air line connections not a very tidy install (well, that and because of my chronic lack of time/patience/skill and total apathy towards how the rig looks!)

You can get much more compact 3-way pneumatic switches, but I do really like the little joysticks - super easy to reach and use - even without looking.

OK, maybe I'm not TOTALLY apathetic about how booty-fab my rig looks - I made this rudimentary cover to cover the valves and just let the joysticks protrude.

If you had any amount of skill you could probably make a tidy little installation of these valves!

I mounted my new CKSA12 compressor inside the rig, up beside the "dash". This way it's kept reasonably clean and dry and has decent, clean air supply.

It isn't exactly "whisper quiet" but if you have no leaks it's cycle time is infrequent and it only runs very briefly to charge the small tank.

In fact, with the sound of a V8 in an open buggy as well as my daughter's constant cries of "Faster, Daddy, faster!" and my son yelling "Use the Cherry Bombs Dad - use the Cherry Bombs!" (I think he thinks they're some kind of "switched" thing like Nitrous instead of me just planting my foot on the idiot pedal) - I hardly hear it at all!

Of course, if you have such extravagant luxuries as, oh say, doors and a roof and a hood, you could easily tuck it away in the engine bay and never hear it at all.

I particularly like that it's well protected where it is.

And this is the great thing about the CKSA12 - it's so small you can mount it anywhere and be worry free because you have a completely independent system to run your lockers.

Nothing's worse than having lockers that don't work - and now I don't have to worry about broken fan belts on an OBA compressor or running out of CO2 in a tank.

The CKSA12 has 2 supply ports - one is used for each solenoid in a "normal" installation.

I supplied both my pneumatic switches from a single port (on the left in this pic) using a T-fitting at the switches so that I had the other port free.

As you can see, to this free port I added a manual valve and quick-connect fitting. This way, if I ever do have a problem with the compressor, I can hook up virtually any other source of air to charge the small tank and retain full locker capability without having to mess around with the air lines.

Speaking of air lines - you may have noticed that in an earlier picture I talked about connecting the 5mm ARB blue air line to my pneumatic switch using a 3/16" compression fitting - but in these more recent pics I'm running 1/4" SAE air brake hose from the switch.

Since here in Canada the ARB line is harder to come by than 1/4" air brake hose (which can be bought almost anywhere for pennies a foot) I decided to minimize the use of the 5mm line. That way I have a coil of the 5mm line (that came with my ARB locker) for spare/repairs that, because I use only a small length, will last a very long time.

Everywhere else I use the cheap, readily available 1/4" line.

The only place I use the 5mm is to connect to the axle housing bulkhead fitting, as shown in this pic.

To join the 1/4" air brake hose to the 5mm blue line I used:

1) 1/4" SAE air brake hose
2) 1/4" compression to 1/4" male NPT fitting
3) 1/4" female NPT coupler
4) 1/4" male NPT to 1/8" female NPT adapter
5) 3/16" compression to 1/8" male NPT fitting
6) a short length of 5mm blue air line

This series shows a brand new CKS compressor next to one that was installed in the rear wheel-well of a Land Rover 110 that then spent two solid weeks off road on the beaches of South Australia. The unit was mounted in the gravel blast-zone directly behind the tire - possibly the worst possible location to mount one. After this abuse the unit still runs 100% and dyno'd up to full performance.

ARB CKS Compressor - Runs completely submerged !!!