# Lezyne floor drive pump pressure gauge info



## DennisF (Nov 4, 2011)

I am posting this so I have it for future reference, and in case anyone else has Lezyne gauge issues and has thoughts about replacing the gauge.

The gauge on my new Lezyne HV dirt drive floor pump failed a week after I got it. Lezyne promptly sent me a replacement.

The gauge threads are glued into the pump, so it is necessary to demolish the old gauge to remove it. http://lezyne.com/download/manuals/FLOOR-PUMP-GUIDE.pdf

I wanted to be able to remove the new gauge without demolishing it, so I used pipe dope on the threads instead of the provided threadlocker, and snugged it down finger-tight. The dial is at a crazy angle, but I don't care about that.

The replacement failed after less than a year -- or so I thought. I left it in my van, and after a cold morning, the movement was sluggish. Warming it up did not help.

So I was planning to get a generic industrial-grade replacement gauge. I had kept the old one and used it to match threads on a replacement. No one had ever seen that size thread.

I contacted Lezyne via their web site. They responded promptly via email, advising me that the threads are M8 x .75mm, and 7mm of depth, and offered to replace the gauge yet again at no cost. However, I was disinclined to install yet another Lezyne gauge.

I was unable to find a gauge with that threading, so was planning to drill and tap it to take 1/8" NPT -- there are plenty of gauges that size available.

Well, it turns out that the gauge was not actually defective. I unscrewed it and found that I had been sloppy with the pipe dope, and it had partially plugged the hole leading to the gauge. I cleand it up. While I was at it I disassembled it and lubed the mechanism with slight amounts of Finish Line Stanchion lube (DuPont Fluoro oil). It is now working perfectly and smoother than when it was new!

FYI, the boss in the pump looks plenty big enough to drill out to 1/8NPT. I looked online and the drill size is 0.3390". 11/32" is closest fraction (0.3437"). The gauge opening in the body is just over 2.5".

Anyway, my ineptness aside, the supplied gauge is of apparently of better quality than I thought -- it has seen hard use for almost a year and shows no sign of quitting. If it lasts a few years I will have no problem buying a replacement gauge from Lezyne -- they aren't expensive.

GREAT pump, BTW!


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## customfab (Jun 8, 2008)

That's nice to know. I've had my dirt drive for 2 years of pro use and it's still running strong. I've often thought about replacing the gauge to something that goes to 100 or 120 psi so the pump could double for road use.


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## SpeedStarr (Jan 19, 2012)

Thanks for posting this. I just got this pump and am already having issues with the gauge.


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## DennisF (Nov 4, 2011)

You're most welcome.

What's it doing? My original one passed 70PSI while I was pushing down on the plunger, then snapped back to 0. I took it apart and it appears it wound past a rack gear. I was able to fix it actually, but not sure about the calibration.

Anyway, they'll send you another no problem.


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