The pivot, as per the drawing, is the two clevis pins at the bottom. The L arm rotates around the point of the L which lies above the center of the pads. As the top of the L is sucked in by the cable the two bolts that go through to the rear plate and pad pull that plate outwards. Thus the the pads are pulled toward each other onto the disc. There's less than 1/16" total clearance between the pads and disc ( 1/32" each side) .the back plate is 1/4" thick and doesn't flex at all. The main plate is 1/8" and flexes a tiny bit, hardly visible at all.