Front Disc Brakes

Fig 1: Front Disc Brakes

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Each front disc brake assembly consists of the following major components. See Fig 1:

1. Caliper - single-piston, floating type (4)
2. Caliper adapter (3)
3. Pads (Shoe and lining assemblies) (5)
4. Rotor (1)

The caliper is a one-piece casting with the inboard side containing a single piston cylinder bore. The front disc brake caliper piston, is manufactured from a phenolic compound. The outside diameter of the caliper piston is 57 mm.

A square-cut rubber piston seal is located in a machined groove in the caliper cylinder bore. This seal provides a hydraulic seal between the piston and the cylinder wall.

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

Fig 2: Adapter, Boots And Pins

Courtesy of DAIMLERCHRYSLER CORP.

The caliper is mounted to the caliper adapter using two guide pin bolts. These bolts thread into two guide pins (1), slid into the adapter. The pins are lubricated and have boots (2) to seal them in place in the adapter.

Fig 3: Adapter Mounting

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The disc brake caliper adapter is fastened to the steering knuckle using two bolts.

Fig 4: Brake Shoes Mounted In Adapter

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The machined abutments on the adapter position the brake pads and caliper. There are two brake pads (2, 3) per disc brake. One pad is placed on each side of the brake rotor (6). Two abutment shims (upper and lower) (5) ride between the pads and adapter. The pads have springs permanently attached to them to help maintain a distance between the pads and the caliper. When brake pads are replaced, only brake pads meeting the original equipment manufacturer (OEM) formulation (such as Mopar® replacement parts) should be used.

Front disc brakes are equipped with audible wear indicators on the inboard brake pads.

Each front brake rotor (6) is vented to help cool it during and after brake applications. It is mounted on the studs of the front wheel bearing hub.

Fig 5: Front Brake Rotor Comparison

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This vehicle has an optional performance brake system. The sales code for this system is BR4. Although similar in appearance to the other front disc brake systems available (BRB and BRK (Disc/Drum combination) and BRT (Disc/Disc combination)), this system features heavy duty wheel brake components. BR4 front disc brakes utilize brake rotors (4) that have a pad contact surface approximately 5 mm thicker (3) than the standard brake rotors (1). The BR4 brake rotors can be easily identified by a recessed machined area (5) near the hub center.

Fig 6: Standard And BR4 Brake Calipers

Courtesy of DAIMLERCHRYSLER CORP.

BR4 front disc brakes feature larger jaw brake calipers (4) than standard (1) and special adapters (3) to accommodate the wider rotors. Each BR4 brake caliper (4) is marked "Turbo" to allow easy identification.