Chapter 12 Disc Brake System Components and Operation 195
Figure 12-5. A disc brake assembly that incorporates the brake rotor and hub into an integral (one-piece) unit. Compare this to the
sectional rotor/hub assembly shown in Figure 12-4. (Chrysler)
Integral braking
(rotor) and hub
Inner
bearing
Wheel stud
Outer
bearing
Spindle
Shoe and
lining
Wheel
Boot
Seal
Piston
Mounting bolt
Adapter
Mounting bolt
Splash shield
Steering
knuckle
Seal
Caliper
Figure 12-6. An exploded view of a front brake assembly that
uses a splash shield and vehicle wheel to protect the brake
assembly from dirt, water, stones, etc. (Ford)
Spindle Caliper
Splash shield
Rotor
Wheel
installed over the inner surface of the rotor. The rotor’s
outside surface is protected by the wheel itself. The splash
shield is a sheet metal stamping or a molded plastic assem-
bly that covers part or all of the rotor’s inner surface. The
splash shield deflects water and debris from the inside rotor
surface. The shield is usually fastened to the spindle assem-
bly, and is far enough away from the rotor to allow air to
circulate. Some splash shields are designed as air scoops,
directing air over the rotor when the vehicle is moving.
Figure 12-6 illustrates the use of a splash shield and wheel
for protection.
On some rear disc brake assemblies, the shield also
acts as a backing plate to hold the emergency brake shoes.
The shield may be held by the caliper assembly on some
four-wheel drive vehicles’ front brakes.
Front Disc Brake Caliper
The function of the disc brake caliper is to provide a
housing for the hydraulic components and the brake pads.
Calipers are made of cast iron or aluminum. The caliper is
usually attached by bolts to the spindle assembly on the