Brakes and Traction Control: Description and Operation

DESCRIPTION - BASE BRAKES
The base brake system consists of the following components:
^ Brake pedal
^ Power brake booster
^ Master cylinder
^ Brake tubes and hoses
^ Proportioning valve (non-ABS vehicles only)
^ Disc brakes
^ Drum brakes
^ Brake lamp switch
^ Brake fluid level switch
^ Parking brakes

Front disc brakes control the braking of the front wheels; rear braking is controlled by rear drum brakes or rear disc brakes depending on options.

The hydraulic brake system is diagonally split on both the non-antilock braking systems and antilock braking systems. That means the left front and right rear brakes are on one hydraulic circuit and the right front and left rear are on the other.

Vehicles equipped with the optional Antilock Brake System (ABS) use a system designated Mark 20e. It is available with or without traction control. This system shares most base brake hardware used on vehicles without ABS. ABS components are described in detail in ANTILOCK BRAKE SYSTEM.

DESCRIPTION - BASE BRAKES (EXPORT)
Four-Wheel Disc Antilock Brakes are standard on all models.

OPERATION - BASE BRAKES
When a vehicle needs to be stopped, the driver applies the brake pedal. The brake pedal pushes the input rod of the power brake booster into the booster. The booster uses vacuum to ease pedal effort as force is transferred through the booster to the master cylinder. The booster's output rod pushes in the master cylinder's primary and secondary pistons applying hydraulic pressure through the chassis brake tubes to the brakes at each tire and wheel assembly.

The parking brakes are foot-operated. When applied, the parking brake lever pulls on cables that actuate brake shoes at each rear wheel. These shoes come in contact with a hub mounted drum (drum for disc/drum brakes or drum-in-hat for disc/disc brakes) and hold it in place.