Lezyne CNC Dirt Floor Drive O-Rings Replacement

Written By: iRobot

Comments: 7

Lezyne CNC Dirt Floor Drive O-Rings Replacement

Difficulty

Moderate

Steps

Time Required

No estimate

Introduction

If your pump seems to be unable to fill tires to as high of a pressure as should, it may be due to leaking O-rings. Use this guide to replace your faulty O-rings.

Tools

Step 2

Hold the base of the pump steady and twist the barrel counter-clockwise by hand until it completely unthreads.
If you are having troubles stabilizing the base and twisting the barrel, try standing on the base and using both hands to loosen the barrel.
Lift the barrel off the base.
When removing the barrel, be sure not to lose the bump stop O-ring. It may stick to the pump base, may be stuck inside the barrel, or may fall out when you remove the barrel.

It is not entirely necessary to detach the barrel from the aluminium base-- just unscrewing the top cap (step 4) will grant you access to the O-rings in the "piston" bar (see step 5). In my case, the lower ring had shifted-- just putting it back into place restored its valve/pump function. I also wasn´t able to unscrew the barrel--too tight for me!

Thanks for the great guide!

ffdezklett - 07/03/15

Step 3

Lift the pump handle until the top cap is exposed.

Step 4

Place the ends of needle nose pliers into the top cap holes and turn counter-clockwise until the cap is loose.
Finish removing the top cap by hand.
Pull the pump plunger out of the barrel.

Step 5

Use a small flathead screwdriver to remove the plunger O-ring.
Use the screwdriver to remove the upper bump stop O-ring.
Install new O-rings.
Be careful not to over-stretch or cut the O-rings if you are using the screwdriver to install them.

Step 6

Remove the lower bump stop O-ring from the pump base.
Remove and replace the base O-ring.

Step 7

Insert the tips of needle nose pliers into the base cap holes and turn it counter-clockwise until it completely unthreads.
Remove the base cap from the base.
Remove and replace the base cap O-ring.
Re-assemble the pump using these instructions backwards.
Don't forget to set a new bump stop O-ring on top of the pump base before re-installing the pump barrel.

Author

iRobot

Member since: 25/09/09

0 Reputation

6 comments

This Lezyne pump didn't last 4 months before I had to attempt this fix. Too bad I wasn't even able to get the barrel off the base, pretty much factory tightened. I called them again and they told me to go into a local bike shop to have them fix it. Really?! Why don't you fix your faulty product yourself! This will be a "good when it once worked" product. Horrible and unreliable product Lezyne, never again.

Gavin shaw - 04/12/14

My question is why does a $70 pump need to be repaired so often? I have one and am cleaning it and re-greasing it every 3 months. Maybe I need to replace the gaskets. My 20 year old $20 pump has never needed any repair. I replaced it because it would not stay on smooth tube necks and the Lezyne has the screw on.

josephgoebbels - 06/04/15

Tip for removing the barrel - grab a tube and wrap it around the barrel for extra grip. Stick with it for a minute or two and it'll start turning.

matt - 16/05/15

I work at Lezyne, and removing the barrel from the base is not the way to do this. It makes the repair much harder than it has to be, and we do not recommend using the lower bumper as the replacement. Switch the upper bumper visible in step 5 with the piston seal, and ignore steps 1, 2, and 6. Step 7 has nothing to do with the problem being addressed here.

If you are re-greasing it every 3 months, you are using too much grease. The O-ring should just be shiny and no clumps of grease should be visible. If switching the O-rings and wiping off any excess grease doesn't remedy the problem, please contact our customer service department, and we will send you a replacement O-ring. Lezyne stands behind all of our products, and we will work to find a solution for you.

Adam - 20/09/16

If you are using a presta valve chuck, the leaking problem is most likely the small o-ring just inside the threaded part of the chuck. It is the primary seal at the presta valve. It wears out after threading and un-threading the chuck dozens of times because the male threads of the presta valve are cutting into the rubber o-ring. The best solution is to replace the o-ring, however Lezyne doesn't offer to seel this 15 cent part, instead you can buy a $13 chuck! A quick temporary solution is to remove the o-ring and flip it over and re-install it. This will give a new surface to seal against untill it wears out.

D Watt - 23/10/16

Yea this pump is less than a year old and the valve isnt working right. I has a Cinelli pump that worked for over 30 years without repair. Too bad I didnt bring it with me. Guess the Italians out did the Deutche this time.

slerickson01 - 06/09/18