I broke BOTH valves on the morning of the MS150 using my Joe Blow pump. I have been very, very careful since then. I followed someone's advice in a post about positioning the valve on top so that I am pulling down on the pump thingy . That seems to help me avoid wiggling it around too much. I probably need a new pump, but I just hate to buy one. This one is maybe 3 years old. Seems like it should still be ok.