Inside an A/C pump used for on-board air

[Nobody]

Here's a look inside the A/C pump that I used on my Bronco II for a good 8 years. When I first did the conversion back in 1994, I was pretty good about feeding a cap of oil into it before or after each trip. As the years rolled by, eventually I quit oiling it all together. It ran just fine until the day I did the V8 swap and switched to a different pump.

I was curious about what was inside, so I took it apart. Not at all what I expected, six cylinders! I noted at the time that I could still see the hash marks on the cylinder walls. There was also quite a bit of oil inside.

Sorry about the crappy pics. After searching for the hi-res pics for an hour, I realized these were video captures from my old hi-8 camcorder... ahh the days before digital cameras! The pics give you the idea though.

[n16ht5]

wow, good to know. I always worry that I am about to burn it up when I fill all four of my 37s

[Nobody]

When I first converted mine, I was a little worried about it. At the time I didn't know of anyone else running converted a/c pumps. I know of one pump on a jeep cherokee that got really hot, but I think it was bad prior to us converting it. I don't think there is much to worry about. You mentioned you don't run a tank, correct? If that's the case you're only asking the it to pump 25psi vs the 200+ it was design to operate at. I would think it would last forever in those conditions. A little oil here and there would probably still be a good idea though.

[n16ht5]

I used to run a tank.. never ended up using any power tools so I just ran a line straight from the pump to the quick disconnect with an always open chuck.