On Board Air using GM airride suspension compressors - 3/31/2003

I wanted some decent On Board Air, but I didn't feel like shelling out $300 for a complete system. I found a few write up on OBA systems using Air-ride compressors pulled from Lincolns, Caddys and the like.

Pics to follow after install is completed.

Air pumps::

I have no pick-n-pull yards around me, and all the local yards wanted ~$60 for one of these pumps. So, I resorted to ebay. I got one out of a 1988-1984 Lincoln, and another one out of a 1998 GM minivan. I would have liked to have two identical pumps, but they both work.

The compressors have 4 basic parts to them. 1) the motor, 2) the piston, 3) a relief valve, and 4) a dryer. I found that the relief valve on the Lincoln compressor is closed until energized, so I just left that as it is with the wires intact if I ever need it for some reason.

Originally I wanted to ditch the dryer (black cylinder on it), but I couldn't find any type of fitting to go directly to the compressor. So, I modified the dryers.

The Lincoln compressor had 4 holes in it with fittings for the airlines on the Lincoln's suspension. I first removed the fittings. Than I filled the holes with JB weld. After that I drilled and tapped a hole for a 1/4" NPT fitting.

Here are some pics of other pumps, just so you know what to look for:


Air tank::

I also got a small air tank off ebay. It is a fiberglass/aluminum scuba tank that has expired. With shipping it was about $20. I was later informed that scuba tanks have a wall that is about an inch thick to survive the 2000psi needed for scuba. Sure it was cheap, but I could have gotten a thinner walled tank that could take up the same amount of room, but hold more air. And I did find one of those on ebay. I plan on mounting this in the trunk, but have a quick disconnect so I can easily remove it when I need the space.


I originally didn't want to mount them in the passenger compartment, but I couldn't find a suitable place to mount them outside. No room in the engine bay. I had thought about behind the gas tank, but that would get the pumps wet. Behind the front bumper may have worked.

I decided to put them in the right rear quarter panel across from the spare tire. I couldn't just throw them in there so I had to make some brackets. I made the brackets out of aluminum angle sheet. Both compressors had different factory mounts so the two brackets I made were different. I only needed to drill two holes in the quarter panel sheet metal to bolt the mounting brackets to.


I put a simple rocker switch to the right of my transmission shifter. It then goes to the pressure switch than to the two relays for the pumps. Each pump has its own relay. Because I used relays I could light gauge wire and make the switch negative. For the positive side, I ran a 4 gauge cable from the battery to a small fused power distribution center. I know that the 4 gauge cable is over kill for now, but I will eventually put an amp and fog lights in the rear. Each pump has a 20 amp fuse.


Air lines and fittings::

I used about 10 feet of air hose. Several barbed hose connectors, 3 way manifolds, a check valve, pressure switch, quick couples, a pressure gauge and a air valve. This was probably the most expensive part as all this was about $60. Below is a diagram on how I routed the air hose.

Manifolds, airtank assembly, couplers and pressure switch:

Pressure gauge, air coupler and valve for air tank:

The pics below show it almost completed:

Below is the 99% finished system. I still have to make a cover for the trim piece and a mount for the airtank. I am pretty happy with the location I choose to mount the pumps, as they are a perfect fit.:

BTW, those rings that the ratchet ties are attacked to aren't 100% stock. I replaced those shitty rivets with some SS hardware.. They aren't going anywhere.

The finished product:

Some Misc pics: