Using a Sanden Compressor
Instructions on how to
design and install an on-board-air system for your vehicle
by Al Bsharah
On-Board-Air Using a York Compressor
Why do you want an on-board-air (OBA) system?
You can run air-tools when you break something on the
You can air-up your tires when you're done wheelin'
If you have ARB air lockers in your differentials
(like me) it provides a reliable source of air-pressure to actuate
Below is the schematic that I drew (I pretty much stole
the design from Matt Osburn)
for how the system's all plugged in. My system is geared towards
those of you who have ARB air lockers, however, a very similar design can
be used for those of you who don't have an air-type locker. Simply
remove the section with the ARB solenoids and it'll work just the
same. This report covers everything in the diagram except for all
air-lines to the left of the first "T" (to the left of the Check
Valve.) I haven't installed my nerf-air-tanks yet, but will update
this report when complete!
Let's walk through the path of an air molecule, 'eh?
Ok, you first enter the air filter where you are
cleaned of dust and other contaminants. Any kind will do, they
can be purchased at many different hardware stores
Then you're run through a tool-oiler which keeps your
compressor running smoothly. It's important you keep the oiler
full so as not to hurt the compressor. They even make "air
compressor oil" just for this purpose. I think I got my
oiler from Grainger.
The compressor pressurizes the rest of the system by
forcing air out the other side. Picked a rotary-style one out of
a late-80's Ford Taurus/Sable from a junkyard for about 25 bucks.
First you'll hit a check-valve (which I eventually
decided not to install on my system, I still may at a later
time.) A check valve will simply allow air to flow in one
direction and isn't totally necessary. I'm told some air
compressors need them so that air doesn't leak back into them.
Purchased from Grainger.
Let's follow the "T" connector down towards
the Water/Oil trap. This is where all the oil from the
compressor and any water from condensation gets filtered out of the
air system before going to vital components or out your air
line. Purchased from Harbor Freight.
Next is a pop-off valve which is used in case your
compressor system isn't shutting down on it's own like it
should. Usually these are set to just above wherever your air
system runs at, my pressure switch is set to hold between 85-100 psi
(required for the ARB's) so my pop-off valve is set at 125psi.
When pressure runs above the value of the pop-off valve, air will be
released to avoid massive pressure within your system. Purchased
from Grainger, turned out to be a bad one so I had to replace it.
The ARB solenoids then distribute the air to the
differentials, but only when the cab-switch is turned on. When
the switch is turned off, pressure is released between the solenoid
and the ARB so the locker will release. Purchased from ARB.
The next item is the pressure switch. Some are
variable, some are fixed. Mine is fixed to regulate pressure
between 85 and 100 psi. As stated earlier, this is what was
required from ARB and is plenty of pressure for me to run basic air
tools, etc. Purchased from ARB (one-stop-shopping)
Next is the quick-connect where you can attach your
air hose to. Purchased from Harbor Freight.
Now, let's go back to the left of the first
"T". This portion has not been assembled yet but I
will describe it's purpose now and update this page when it is
completed. You'll see that the air-tanks are attached with
cut-off valves. Cut-off valves are used in case an air-tank is
punctured and develops a leak, so I can shut that portion of the
system down and still function properly on the trail. Since I
have air-lockers, I can't afford to have my air system fail on me!
As well, I will eventually put an in-cab pressure
gauge into the system for visual purposes.
On to the install...
||Here is the parts list <grin>. This is a very tedious
project, with an awful lot of small parts that need to be acquired
and assembled. Singularly, they're pretty cheap.
Cumulatively, they sure add up!
||Here you will see the fittings that attach to the axle-housing for
the ARB lockers, in the order they are to be put in. Below is
what the assembly looks like completed. The far-right piece
goes inside the differential, the second piece is screwed into the
differential from the outside. The two small rings are different
sizes, so make sure you get them in the right order! The
leftmost of the two is the one that fits over the blue air-tube the
best, so use that as your test. Be aware that the pieces
between the two rings need to be set up exactly the way they're
shown. The threaded male-male fitting has a bare spot on one
side and that needs to go towards the axle. The rod that goes
through it fits best that way. The rest is fairly
straight-forward in their diagram.
||This is the air compressor. It's from a late-80's Ford
Taurus/Sable vehicle. I chose this because the bolt-holes
seemed to be very close to my stock mount, and these vehicles are
plentiful in junk-yards where I got the compressor (about
$25). Steve McKay fabricated a great mount for it, as you can
see. It's incredibly important that your compressor be mounted
exactly in-line with your belt-system or you'll go through belts
much quicker. This takes some eye-balling and strange
measurement techniques...just don't rush this one.
||This is another picture (albeit a crappy one) of the compressor
mount that was fabricated.
||Here you can see the air-intake and the tool-oiler going into the
input of the compressor. The red hose is simple heater-hose
from NAPA. It doesn't hold any pressure, so nothing fancy is
||Ta-daa! Completed system, without any of the wiring
harnesses installed. Teflon tape is your friend. Use it
HEAVILY! After I got everything connected, including the new
belt, pulley, wiring harnesses, switches, I found a number of small
leaks. I ended up pulling many sections apart and re-doing
them. This is not fun, so do it right the first time! I
used my stock jack mount to locate and fix the manifold in
place. Zip-ties are as good a friend as teflon tape is!
||Here you can see the air cleaner (blue) coming from the output of
the compressor. This goes towards the manifold which is
described below. Heavy-duty air-conditioning hose was used for
reliability. It's expensive, a bit overkill, but worth it to
||Here's the best view of the manifold. Most of the
"T" fittings, male-male and other connectors were from
Harbor Freight, but you can get them from most Home Depot's and
hardware stores for a little more money. Starting from the
right you can see the quick-connect, the pop-off valve, the pressure
switch, and the front/rear ARB solenoids.
here will allow you to voice your opinions about this page (discussion
Be sure to check out Kilby Enterprises' OnBoardAir.com
for mounting brackets, pulley accessories and other goodies for your OBA