Caddy Compressors
This page outlines the procedures I used to modify two cadillac compressors
for on-board air.
Having the freedom of going off roading
and knowing there is a source of air after the trail is a great feeling. These
sources of air include the Powertank, ViaAir air compressor, converting the
air conditioning compressor and other various 12V air compressors. However,
for those of us who are on a budget and like air conditioning, there aren't
a lot of choices for that source of air. Every air compressor that is inexpensive
also has a low flow rate, short duty cycle, and will not last long.
Although the caddy air compressors are slow, they are still faster than the
cheap Wal-mart specials. 1980's cadillacs used an air ride suspension system
and to pressurize the system a 12V air compressor was used. The air compressor
can be found on the driver's side of the engine compartment. Be sure to get
the mounting brackets too. Some compressors are known to be made with plastic
pistons and I'd assume these are on the late 80's caddies. I'd recommend looking
for the early 80's models.
First, I obtained two caddy compressors from the junkyard for $20 each. They
were a lot smaller than I thought which was good because I still hadn't figured
out where to mount them. I took them apart to see how they work and see how
I can improve the flow.
From my research I found that I could remove
the electronic bleed off valve and the desiccant chamber. The electronic bleed
off valve allows the cadillac suspension system to release air pressure and
the desiccant chamber dries the air before it is released to the system. I didn't
need the desiccant chamber because my air tank is stainless steel and should
not rust, besides, I'll just empty it a couple times a year.
Once removed, the electronic bleed off valve will leave a hole that needs to
be plugged. Also, by removing the desiccant chamber I had opened up a hole that
couldn't be used for air hose attachment. To plug these holes I JB welded them
shut, as shown in the picture below.
However, with the output port plugged, how
do I get air to the tires? Well, the best place to attach an air hose is the
schraeder valve on the top of the compressor. It's the perfect size for the
1/4 inch ID of the hose, but the ID of the schraeder valve is tiny. I ended
up drilling the valve larger to 7/32".
In an attempt to provide the compressors with clean air I loosely stuffed oily
foam in the area where the electronic bleed off valve was as shown in the above
picture. I then punched out the sheet metal circle on the side of that chamber
and sealed the opening on the top plate with aluminum foil as shown in the picture
below.
Other than general cleaning, that's all
I did to the compressors. Now I needed a place to mount and wire them. Not wanting
to move anything in the engine compartment I looked under the 4Runner. I found
lots of space above the rear axle and to my surprise it was relatively clean,
no mud splatters. And as for water crossings, that part of the body is about
8 inches above the bottom of the door sills, so at that point I think I have
more things to worry about than getting the compressors wet. Besides, I don't
think enough water can get in the compressors to do any damage, it's not like
I'm running them while crossing a stream.
So I drilled some holes in the body and screwed them there. I then ran some
air hose from the two compressors into a manifold and into the inside of the
runner. There I have a length of hose long enough to reach all 4 tires from
inside or I can attach my air tank and fill it up.
So how long does it take to fill up the
tank and fill up the tires?
Tire, (1) 32x11.5 inch Pirelli Scorpion AT :
It takes 5 mins to fill from 10 PSI to 32 PSI.