Tourist in MSN: I bought a Joe Blow in Early March 2014 when I picked up my bicycle. I primarily use it for the bikes with the schrader valves. I recently replaced the leather piston in my 1990s Silca Super Pista. I used there leather conditioner on it prior to instal per there directions. If you haven't conditioned the leather recently, I would try that to see if you don't need to stretch the leather any longer. I also bought the Hiro pump head from Silca and It is a big improvement. In the past I have destroyed a couple of presta valves removing the chuck from the presta valve. The Hiro negates that possibility.