Front Disc Brakes

Front Disc Brake Caliper Assembly:

The front disc brakes consist of the following components:
- Brake caliper - single-piston, floating type
- Brake shoes and linings
- Brake rotor
- Hub

When the brakes are applied, fluid pressure is sent to each brake caliper. The pressure at the caliper is exerted equally against the caliper piston. The pressure applied to the piston is transmitted directly to the inboard brake shoe. This forces the shoe lining against the inner surface of the brake rotor. At the same time, fluid pressure within the caliper piston bore forces the caliper to slide inward on its guide pins. This action brings the outboard shoe lining into contact with the outer surface of the brake rotor. This pressure on both sides of the brake rotor causes friction, bringing the vehicle to a stop.

BRAKE CALIPER
The caliper is a one-piece casting with the inboard side containing a single piston cylinder bore.

Front Disc Brake Caliper (Exploded View):

The front disc brake caliper piston, is manufactured from a phenolic compound. The outside diameter of the caliper piston is 84 mm.

Fig. 2 Piston Seal Function:

A square-cut rubber piston seal is located in a machined groove in the caliper cylinder bore. This provides a hydraulic seal between the piston and the cylinder wall. The piston seal is designed to pull the piston back into the bore of the caliper when the brake pedal is released. This maintains the proper brake shoe-to-rotor clearance.

A rubber dust boot is installed in the cylinder bore opening and in a groove in the piston. This prevents contamination in the bore area.

Front Disc Brake Caliper Mounting:

The caliper is mounted to the steering knuckle using bushings, sleeves and two guide pin bolts that thread directly into bosses on the steering knuckle.

Two machined abutments on the steering knuckle position the caliper. The guide pin bolts, sleeves, and bushings control the side-to-side movement of the caliper. All of the front brake force generated during braking of the vehicle is taken up directly by the steering knuckles of the vehicle.

BRAKE SHOES AND LININGS
There are two brake shoes mounted to each caliper, one inboard and one outboard. The brake shoe lining material is a semi-metallic formula. When brake shoes are replaced, only brake shoes meeting the Original Equipment Manufacturer (OEM) formulation (such as Mopar replacement parts) should be used.

As front disc brake shoe linings wear, master cylinder reservoir brake fluid level will drop. Fluid level should be checked after replacing shoes.

Front disc brakes are equipped with an audible wear indicator on the outboard brake pad. This sensor emits a sound when the brake lining may need inspection or replacement.

BRAKE ROTOR
Each front brake rotor is vented to help cool it during and after brake applications.

HUB
The hub mounts the brake rotor to the vehicle's drivetrain and tire and wheel assembly. For service of the front hub or its wheel bearing, refer to Transmission and Drivetrain.