The Compressor
The compressor I chose was a York compressor,
which I got out of an AMC Eagle or Concord (or
something like that) at a junkyard. York compressors
are better for on-board air since they have their own
oil reservoir, and don't let any of the oil get into the
air you're trying to compress. They also put out more
volume than other automobile compressors. The
picture to the left shows the compressor, with the
mounts still on it, as I pulled it from the car (and after I scraped away a small portion of
the grime from the mount). As you can see, it was pretty dirty...
When you pull a compressor out of a donor car, it's important to try & get the brackets it mounted on, as well as the hoses (or at least the fittings with a foot or so of hose) for input and output. It's easy to get a barbed fitting to attach to whatever hose comes off the compressor -- it's much harder to find (after the fact) the proper fittings that will work with the compressor. You may also need an idler wheel for the belt, since the York compressor (at least on the bracket set I got) doesn't adjust by itself.
You will need to check two things with the compressor before you buy it:
- The magnetic clutch must work. This can be tested by grounding the compressor casing on your vehicle, and touching the wire coming off the compressor to the (+) terminal on your battery. The clutch should click, and the outer pulley should now turn the inner part, and the compressor shaft as well. When you remove power from this lead, the outer pulley should freewheel, without turning the compressor.
- The compressor must turn over, and pump air. You can check this by turning the inner portion of the pulley (or the outer portion if you have the pulley engaged as above), and seeing that the output hose blows air and the input hose sucks air.
I picked up my compressor at a place called "Pick-Your-Part", in Hayward, CA for $22. I paid a dollar to get in, and had to look around for about an hour before I found a donor AMC car with a York compressor.
Once I got the system up and running, a "flaw" in my
compressor became apparent: it would run for a few
seconds, and then lock up hard. It wasn't seizing, since I
could turn it backwards, but it wouldn't turn forwards. So, I
went to a different junkyard (one much closer to home) and
pulled a much newer looking York off a Volvo. Since I still
had the brackets off the original compressor, it didn't much
matter what car I got the compressor from. Total cost (with
warrantee): $40.
Go back to my On-Board Air page.