Lining puck Brake disc Brake housing Screw Gasket Gasket O-ring packing Piston Adjusting pin Brake return spring Spring guide Internal retainer ring Fluid inlet bushing Gasket Bleeder adapter Bleed valve Bleed screw Washer O-ring packing O-ring gasket Cylinder head Washer Adjusting pin nut Pin grip Piston Fluid inlet port Wheel Key Disk Pressure plate lining puck Backing plate lining puck Brake housing Return spring Automatic adjusting pin or wear indicator pin Adjusting pin grip 13-44 Figure 13-80.  A cross-sectional view of a Goodyear single-disc brake caliper illustrates the adjusting pin assembly that doubles as a  wear indicator. Figure 13-79.  An exploded view of a single-disc brake assembly found on a light aircraft. 