Originally Posted by
jdswitters
I made a disparaging remark about my PB mini pump yesterday. I figured out how to fix it last night for those interested, although having dissembled it and seeing how it is put together, I still plan on taking a Lezyne on tour this spring.
If you cant get the pump head over the schrader valve enough to get air in the tube cut 1/8 inch off of the rubber tube piece that is directly under the screw-on cap on the pump head. This brings the little nub at the bottom closer to the top of the schrader valve body. You may find that you dont need to do this with some tubes and with others it is a necessity.
Those have a similar design to Topeak that I have. I think you may have made a mistake cutting that part.
Those pumps can work on both Shrader and Presta but you have to reconfigure it. To do so you have to unscrew the cover pull out the rubber seal. under the rubber seal is a plastic piece that installed one way works on presta Fliping it over put a tab out that will press the valve in Shrader. I think you have the plastic peice in wrong.