Q:

Air Force Pump going bad?

I have a fairly new Air Force pump (yes, I know, but I bought it before I discovered this site and learned that there are better pumps). I have used it maybe 10 times. On two occassions, I stared to get a hissing sound (some kind of leak) after pumping to maybe 2500psi. The first time, I opened the valve, removed the cylinder and re-started and everything was fine. The second time, I simply drained the pressure relief, closed the valve and re-started. Again, everything was fine. But I’m worried that this shouldn’t be happening at all. Any suggestions? Is this just an idiosyncracy of the pump, or is the pump already going bad?

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I had the same problem. I put soapy water on everything and found the gauge was leaking. I took the pressure gauge cap off. a solder joint had a pin hole. The higher the pressure the more it hissed. Had to put on a new pressure gauge.

O.k., thanks. I’ve been pretty careful not to go over the recommended 5 minutes pumping time. The pump dies get warm, but not hot. If it happens again, I’ll see if I can find the source of the noise.

The next time you hear a hissing sound, try to locate the source by placing your ear to where the sound is coming from. Most often, it’s just a matter of finger-tightening the screw(s) on that particular area. Also, clean the seals or surfaces of the screws or o-rings (especially the one on the fill adapter that comes with the pump to fill an Airforce rifle). Believe it when I say that even a hair that gets lodged in between the o-ring and bottle will cause a leak.

For pump maintenance and to extend its life, all you need to do is make sure that you stop pumping when the base gets very warm. Then bleed the hot air out by unscrewing the bleed screw quickly. I have to stress out that you need to do it quickly and not slowly as you want to let all the built-up moisture out. Continuing to use the pump when it’s hot will cause o-ring burnout. Once this happens to the o-ring located on the base of the pump, the entire unit will fail.

When my Airforce handpump went bad, I tried very hard to disassemble it to get access to the failed o-ring, but it is not a pump that is very user-serviceable. So, I ordered the new Ultra-Glide handpump. It is a new-style pump that gives the user easy-access to the most vulnerable o-ring that exists on all portable high-pressure handpumps. When it goes, all I’ll have to do is remove one screw on the base to get access to the o-ring.

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