Pin Calipers Pictures?

With the pin calipers, the pads are really hooked into the big caliper. The pins just keep the pads from sliding into the hub by gravity and hold the caliper to the caliper adapter. The caliper slides into the caliper adapter.

The caliper bolts will hit the inside of the rim before falling out. And if there are no bolts the pads will slide 1/2" or so and rub the brake hub, but still contact most of the caliper piston to stop the car. And make a bunch of noise from the rubbing. And then the caliper can slide into the rotor too and rub, but still stop the car. So there's about 3 fail safe features to prevent catastrophe.