Replying to Rossi Pro Axial 120 and 140 problems.

Recently I picked up both pairs of these bindings and ive been using the 120 on some old chronics for  2 weeks or more. The brakes for these continually fall off. I mean literally fall off the ski. The one screw that holds each of the brakes in becomes unthreaded and falls off the ski when i take the ski off. So far this has happened about 6 or seven times and I was just wondering if anyone else had this problem and how they went about fixing it. also would it be smart for me to find a longer bolt, or could that be dangerous.