I've now gone through two brake lines (on my third) without even adjusting the barrel. I think (If I remember your bike correctly) we have the same brakes. I now never go anywhere with out a spare cable (sized for the rear; better to long for the front brake than to short for the rear). I would tell you how to keep that from happening, but I don't really know other than to say adjust the clampy thingy that holds the cable to the caliper as little as possible (If you want, I could prolly explain that a bit better).