I have a variety of small bike pumps, both mini-pumps like a Topeak Race Rocket and small floor-pumps like the Topeak Road Morph. They live on their bike all the time, and suffer the same vibrations and moisture and dirt as the rest of the bike.
What maintenance should be done to ensure the pump will work when required, and how often?
Related - do Gauges and CO2 fittings and hoses need special consideration ?
I'm on my second Road Morph Road Morph(or third, I can't remember whether the stolen one was a Road or Mini Morph), and I had a couple of issues with the first (second?).
The gauge partially stuck, causing me to blow out a tyre (a studded winter tyre rated max 85 psi, with the suggestion to run close to the max if there's no snow). I pumped it until I was sore and blew the sidewall out a few minutes later. Later testing suggested I'd got well over 100psi and the tyre was far from new. When I opened up the gauge it was full of rusty water and the spring was rough with rust. That had been left on my bike all winter and our winters are wet.
While on a long tour, I found however hard I worked I couldn't get my tyres as firm as I'd like, barely enough to ride on. At a campsite, I stripped it down and regreased the O-ring in the main barrel, which sorted the problem . A couple of years later I replaced the O-ring*, and a couple of years after that went to regrease it but stripped the (rather fragile) screw thread that retains the output tube. It no longer sealed there, but I salvaged parts from a Mini Morph to repair it. Be gentle in that area of the pump.
The reason I replaced it in the end is that I destroyed the top cap trying to strip it again for cleaning/greasing. You can use the T handle to unscrew the cap that it bayonets into for storage, and withdraw the piston, but only if it's not jammed. This was jammed and my other tools trashed the plastic.
So in summary, every year or two depending on conditions, strip and regrease the main O ring. Test the pump and gauge occasionally by pumping a tyre to full pressure with it, using either another gauge to check, or a thumb and common sense.
* I couldn't find a replacement O ring for that pump, but managed to find one in a set meant for plumbing
For the most part, I think the pumps will be fine as they are. Think about how many pumps out there never see a single bit of maintenance yet still work perfectly fine. However, in the interest of long-term reliability, I can come up with a few valid maintenance concerns (ordered from most to least frequently encountered):
It's probably also good practice to "exercise" the pump every so often (a few times a year?) to A: distribute and refresh the lubricant, and B: ensure the pump still works.
I’ve used Lezyne Pressure Drive and Sport Drive pumps for ~10 years in all weather and over tens of thousands of kilometers. They are mounted to the bottle cage so see a lot of dirt and water. I pretty much only use them when I have a puncture while on the road.
My only issue so far has been that the threads of the (removable) hose where it screws onto the valve failed after not too many uses (maybe 20). Fortunately it still barely engaged for the last time I needed it and I ordered a replacement hose. Kind of surprising and disappointing.
Every few years I open the pumps, clean them and lubricate with silicone lubricant. They all still work smoothly.
