Chevrolet Silverado / GMC Sierra. Service manual — part 2686

Fig. 50: Adjusting Parking Brake Shoes Using Special Tool
Courtesy of GENERAL MOTORS CORP.

2. Position the J 21177-A over the shoe and the lining at the widest point.

3. Turn the adjuster nut until the lining just contacts the J 21177-A .

Specification: Park brake shoe to brake rotor clearance: 0.6604 mm (0.026 in)

4. Repeat steps 1-3 for the opposite side.

Park Brake Cable Tension Adjustment

2008 Chevrolet Silverado 1500

2008 BRAKES Park Brake - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

1. Verify the self adjuster lock-out pin has been removed.

2. Fully apply and release the park brake pedal 3 times.

DESCRIPTION AND OPERATION

PARK BRAKE SYSTEM DESCRIPTION AND OPERATION (W/REAR DRUM)

System Component Description

The park brake system consists of the following:

Park Brake Pedal Assembly

Receives and transfers park brake system apply input force from driver to park brake cable
system.

Park Brake Release Handle Assembly

Releases applied park brake system when pulled.

Park Brake Cables

Transfers input force received from park brake pedal, through park brake cable equalizer,
to park brake apply lever.

Park Brake Cable Equalizer

Evenly distributes input force to both the left and right park brake units.

Park Brake Apply Lever

Multiplies and transfers input force to park brake actuator/adjuster.

System Operation

Pressing the Park Brake Pedal creates INPUT FORCE. The INPUT FORCE is transferred and
evenly distributed through the park park cables and the equalizer to the left and right rear park
brake cables. The INPUT FORCE, is then transferred to the apply levers located in each of the

IMPORTANT: Before you adjust the park brake cable tension, verify that the

park brake shoes are adjusted to provide a clearance of 0.6604
mm (0.026 in) and the rear disc brake rotors are installed.

2008 Chevrolet Silverado 1500

2008 BRAKES Park Brake - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

rear brake drums. The levers then multiply the INPUT FORCE and transfer the force to the rear
brake shoes. At that point, the brake shoes are forced to expand and make contact with the
friction surface of the rear brake drums, preventing the rotation of the rear wheels. Use the park
brake release handle to disengage the park brake.

PARK BRAKE SYSTEM DESCRIPTION AND OPERATION (W/REAR DISC)

System Component Description

The park brake system consists of the following:

Park Brake Pedal Assembly

Receives and transfers park brake system apply input force from driver to park brake cable
system.

Park Brake Release Handle Assembly

Releases applied park brake system when pulled.

Park Brake Cables

Transfers input force received from park brake pedal, through park brake cable equalizer,
to park brake apply lever.

Park Brake Cable Equalizer

Evenly distributes input force to both the left and right park brake units.

Park Brake Apply Lever

Multiplies and transfers input force to park brake actuator.

Park Brake Actuator/Adjuster

Uses multiplied input force from apply lever to expand park brake shoe toward the friction
surface of the drum-in-hat portion of the rear brake rotor.
Threaded park brake actuators are also used to control clearance between the park brake
shoe and the friction surface of the drum-in-hat portion of the rear brake rotor.

Park Brake Shoe

2008 Chevrolet Silverado 1500

2008 BRAKES Park Brake - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Applies mechanical output force from park brake actuator to friction surface of the drum-in-
hat portion of the rear brake rotor.

System Operation

Park brake apply input force is received by the park brake pedal assembly being depressed,
transferred and evenly distributed, through the park brake cables and the park brake cable
equalizer, to the left and right park brake apply levers. The park brake apply levers multiply and
transfer the apply input force to the park brake actuators which expand the park brake shoe
toward the friction surface of the drum-in-hat portion of the rear brake rotor in order to prevent
the rotation of the rear tire and wheel assemblies. The park brake release handle assembly
releases an applied park brake system when it is pulled rearward.

SPECIAL TOOLS AND EQUIPMENT

SPECIAL TOOLS

Illustration

Tool Number/ Description

J 21177-A

Drum-to-Brake Shoe Clearance Gauge

J 37043

Parking Brake Cable Release Tool

2008 Chevrolet Silverado 1500

2008 BRAKES Park Brake - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado