Hydraulic System: Description and Operation

Brake Warning System Description and Operation

Brake System Indicator
The IPC illuminates the brake indicator when any of the following occur:
^ The IPC detects that the park brake is engaged. If the vehicle travels 3 - 15.2 meters (1 - 50 ft.) with the park brake engaged, the IPC sends a class 2 message to the BCM in order to activate an audible warning.
^ The IPC detects a low brake fluid condition. The IPC sends a class 2 message to the BCM in order to activate an audible warning.
^ The IPC performs the displays test et the start of each ignition cycle. The indicator Ruminates for approximately 5 seconds.
^ The IPC detects a loss of class 2 communications with the EBCM and the discrete back-up ABS indicator signal circuit is high.

Hydraulic Brake System Description and Operation

System Component Description
The hydraulic brake system consists of the following:
Hydraulic Brake Master Cylinder Fluid Reservoir: Contains supply of brake fluid for the hydraulic brake system.
Hydraulic Brake Master Cylinder: Converts mechanical input force into hydraulic output pressure. Hydraulic output pressure is distributed from the master cylinder through two hydraulic circuits, supplying diagonally-opposed wheel apply circuits.
Hydraulic Brake Pressure Balance Control System: Regulates brake fluid pressure delivered to hydraulic brake wheel circuits, in order to control the distribution of braking force. Pressure balance control is achieved through Dynamic Rear Proportioning (DRP), which is a function of the ABS modulator.
Hydraulic Brake Pipes and flexible Brake Hoses: Carries brake fluid to and from hydraulic brake system components. Hydraulic Brake Wheel Apply Components: Converts hydraulic input pressure into mechanical output force.

System Operation
Mechanical force is converted into hydraulic pressure by the master cylinder, regulated to meet braking system demands by the pressure balance control system, and delivered to the hydraulic brake wheel circuits by the pipes and flexible hoses. The wheel apply components then convert the hydraulic pressure back into mechanical force which presses linings against rotating brake system components.

Brake Assist System Description and Operation

System Component Description
The brake assist system consists of the following:
Brake Pedal: Receives, multiplies and transfers brake system input force from driver.
Brake Pedal Pushrod: Transfers multiplied input force received from brake pedal to brake booster.
Vacuum Brake Booster: Uses source vacuum to decrease effort required by driver when applying brake system input force. When brake system input force is applied, air at atmospheric pressure is admitted to the rear of both vacuum diaphragms, providing a decrease in brake pedal effort required. When input force is removed, vacuum replaces atmospheric pressure within the booster.
Vacuum Source: Supplies force used by vacuum brake booster to decrease brake pedal effort.
Vacuum Source Delivery System: Enables delivery and retention of source vacuum for vacuum brake booster.

System Operation
Brake system input force is multiplied by the brake pedal and transferred by the pedal pushrod to the hydraulic brake master cylinder. Effort required to apply the brake system is reduced by the vacuum brake booster.