- a few suggestions:

1. don't use a lot of finger torque when opening/closing the presta valve

2. don't use a twisting motion when removing the pump head from the valve

3. throw away the stem nut and cap that come with the tube

4. use a long-valve presta and hold the stem when attaching/removing the pump head

5. buy a better tube? (but honestly, i've never had trouble with any regular presta tubes - with the exception of three Performance's thorn-resistant tubes, all of which separated at the stem base)