I have a Lezyne Sports Drive floor pump. It has worked fine for a couple of years, and it lives in my garage. The handle is stored in the down position, so the cylinder is mostly empty. The pump sits on the concrete floor.

enter image description here Mine has an older style of chuck on it though.

Today I went to use it while patching a road tyre, and pushing the handle was hard, and there was no air entering tube till the gauge hit 80psi. The tube was not at 80psi - it was naked and maybe held 5-10psi.

I checked the schrader/presta adapter/pressure release thinking something was stuck in it, but that's just a threadded tube and was clear.

So I checked with the hose nozzle in my and it blew air with no resistance. BUT it was very cold and my hand got damp. Imagine a wet sneeze, but cold.

Aiming the hose at a clean dry surface, I gave it a pump and there's moisture visible. 30-40 pumps later the moisture is much reduced.


  • Does my pump have water in it?
  • How did water get in there?
  • How do I get it out?
  • 1
    After dry pumping the moisture out, does your pump now work?
    – RoboKaren
    Jan 3, 2017 at 1:06
  • 2
    It's not unusual for a little condensation to form in a pump, especially if it's used on a warm, humid day, then put away. When you then try it on a cold day (especially if stored in a cold space) you will likely get some moisture. In extremely cold weather the moisture might freeze and plug the pump or cause its valves to fail. You will not see the situation that can occur with tank-type compressors, where large amounts of moisture collect in the tank -- the physics just don't allow that. You could have moisture build up from several "cycles" of pumping and putting away, however. Jan 3, 2017 at 1:33
  • p.s. I have the exact same pump, it's a beauty. :-)
    – RoboKaren
    Jan 3, 2017 at 1:34
  • 1
    There is another odd way for moisture to get into the pump. First, fill your tire using an air compressor which is not properly drained -- it's not unusual to find tires with substantial amounts of water in them from this. Next, attach your pump to such a tire when the tire pressure is relatively high. Before you manage to pump air into the tire, the tire may blow water backwards into the pump. Generally this water would get no further than the hose, as the valve at the base of the pump would prevent backflow, but then when the pump is put away the water could seep past the valve. Jan 3, 2017 at 3:17
  • @RoboKaren yes, the pump works better now its dried out, on the same tube it was failing before. I'll store it on the workbench and see if that helps.
    – Criggie
    Jan 3, 2017 at 5:19

3 Answers 3


Yes, floor pumps can condense water in them. The water is from atmospheric water vapor. When the pump walls are colder than the surrounding air, the vapor can condense just like dew forms on leaves in the morning. Temperature swings assist in the formation of dew and this is made worse by leaving it on concrete, which is not only often much colder than the surrounding air, but also retains moisture.

After a while, the moisture in the pump will build up to the point where it has to get blown out the next time you use it. Especially, pumps like the Lezyne (which I also have) which are single-action designs, the top of the pump is open to atmospheric air and so the moisture can easily condense on the inner walls above the piston and trickle down into the main chamber.

How to get rid of it:

1) Easy way: Dry pump a few times (i.e., pump it a few times with nothing attached) until nothing comes out. If you can do this outside in the sun, even better.

2) Slightly harder way: Do #1 first, then disassemble the top of the pump so that it's open to air. Take the piston out. Let everything air dry or dry on top of a radiator. While you have it apart, grease the piston seal slightly with the vendor approved lubricant -- usually any light silicon grease that is safe for teflon/rubber/leather.

How to prevent it from happening

Don't store your pump in a basement or garage where there is cool/damp air. Keep the pump off concrete. Store it somewhere where there is cool/dry air (best) or warm/dry air (second best).

If that's not an option, you could also hang the pump upside down (with the handle in the stored configuration) so that any condensate that forms in the piston or on the handle will drip down. Keeping it away from the concrete floor would be an added bonus.


Finally, here's a youtube video made by Lezyne showing how to overhaul their pump:


How cold is it? Sounds like condensation from the cold concrete.

Hang it up off the floor and see if the problem goes away.

Hopefully there is no rust inside! Maybe you need to open it and clean it. Theres a black plastic ring which should unscrew and let you lift the whole plunger up and out. Look it over, re-lube it and reassemble.

At worst you might need to store the pump inside not in a cold garage.

  • Well at the moment its 30 degrees C and summer, so the moisture will likely be building over the last couple years.
    – Criggie
    Jan 3, 2017 at 1:39
  • 1
    @Criggie - It's unlikely that the moisture could have built up for years, as any time you use it you will blow out most of the accumulated moisture. Jan 3, 2017 at 3:12
  • @DanielRHicks Strange - I use it at least every couple weeks.
    – Criggie
    Jan 3, 2017 at 5:19
  • 1
    @Criggie - And how cold does it get at night? 30C air can contain a lot of moisture. Think of a cold beverage glass "sweating". Jan 3, 2017 at 12:28

Humidity in the air drops out as water.

This happens with the temperature drops.

And it happens with compression. So if the air is high humidity just compressing will condense water out of the air.

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