Where did you get the sorbo from? I know that many pads on places like eBay are out of a weak material that breaks apart easily. I personally bought a polyurethane sheet off of McMaster-Carr and cut them myself and they are very durable and dense. (70d) I haven't had one fall apart yet, but they haven't had too much testing. Also, in my MB03 I have a sorbo pad glued on my piston instead and I cut it down to a cone-ish shape and it works pretty well. I believe that pad is only 50d though. If I take it apart later I'll post a picture if I remember to.