I'm trying to put my front brakes back together. The hardware kit for the front calipers has a metal hold down plate, a small 'anti-rattle' spring, and something that looks like a black 'rubber band'. 2 plates, 2 springs, and 2 'rubber band' things for each caliper. I can see, from my old ones, how the hold down plate and the anti-rattle spring go together, but where does the 'rubber band' go?