The Brake System:
Disc Brakes
 The disk brake, like the drum brake assembly, is operated by pressurized hydraulic fluid. The fluid, which is routed to the calipers through steel lines and flexible high-pressure hoses, develops its pressure in the master cylinder.
Image Right:Disc Brake Assembly
Once the brake pedal is depressed, fluid enters the caliper and begins to force the piston(s) outward. This outward movement forces the brake pads against the moving rotor.  Once this point is reached, the braking action begins. The greater the fluid pressure exerted on the piston(s) from the master cylinder, the tighter the brake pads will be forced against the rotor. This increase in pressure also will cause an increase in braking effect.
As the pedal is released, pressure diminishes and the force on the brake pads is reduced. This allows the rotor to turn more easily. Some calipers allow the brake pads to rub lightly against the rotor at all times in the released position. Another design uses the rolling action of the piston seal to maintain a clearance of approximately 0.005 inches when the brakes are released. |