Chapter 12 Disc Brake System Components and Operation 181 Copyright by Goodheart-Willcox Co., Inc. Small amount of fluid Piston Pads Caliper A New lining B Worn lining Large amount of fluid Rotor Delco Figure 12-8. A—Brake pads that are new result in a small amount of brake fluid behind the piston. B—The pads have worn down, causing piston to travel farther out in its bore to maintain the correct rotor-to-pad clearance. There is now a larger volume of brake fluid behind the piston. Nissan Bleeder screw Dust boot Sliding bushing Dust boot Torque plate Dust boot Dust boot Brake caliper Sliding bushing A B Bleed screw Mounting bolts Caliper body Mounting bolts Silicone grease on pins Pin boots Caliper bracket Toyota Figure 12-9. Two styles of floating (sliding) caliper brake assemblies. A—One-piston setup. B—Two-piston arrangement. Compare both.