Last week I swapped my Topeak Road Morph pump from Presta to Schraeder and back to help a guy with a low end bike get to a shop. Looks like I did not tighten the cover of the valve assembly enough when I put it back together. At the end of the ride it was missing. At least the fiddly little bits inside were there. I contacted Topeak customer service on the net and they are sending me a new part, no fuss, and no charge.