Brake System: Overview

Overview









The vehicle has two brake systems that are independent of each other:
- The foot brake, which is controlled using a brake pedal. It acts on all four wheels through a hydraulic system. The foot brake is a disc brake.
- The parking brake, which is either operated by a mechanical pedal or an electric parking brake. The electric parking brake is integrated in the brake caliper and is a disc brake.
The power brake booster is actuated directly by the brake pedal. It ensures that less pedal force is required when braking with the aid of vacuum from the vacuum pump and/or the intake manifold for the engine.

Brake system
The brake control system comprises:
- Anti-lock Braking System (ABS)
- Electrical Brake force Distribution (EBD) at the rear wheel brakes.
- Dynamic Stability and Traction Control system (DSTC)
- Emergency Brake Assistance (EBA).
- Fading Brake Support (FBS).
- Ready Alert Brakes (RAB).
As well as on vehicles without a vacuum pump:
- Brake Pressure Support (BPS).
For further information about ABS, DSTC, brake assistance and EBD, see Design and Function, Brake control module (BCM).

Fading Brake Support (FBS)
Fading Brake Support aids the driver to increase the brake pressure in the system in the event of hard braking. This is to compensate for the high pedal force that is normally needed when the brake discs are hot.
The system detects the pressure in the main cylinder set against the vehicle's retardation. If retardation is not sufficient, the pressure increases from the hydraulic unit to both circuits until maximum retardation is achieved.
The pressure in both the circuits increases until ABS control is achieved.

Pressurization of Ready Alert Brakes (RAB).
The brake system is pressurized to prepare the brake system for any panic braking.
The system detects the speed at which the driver released the accelerator pedal. If this occurred quickly, the hydraulic unit starts and prefills the brake calipers. This is to eliminate any clearance between the brake pads and discs, which shortens the reaction time of the brake system.
In order for the system to activate, the driver must not have braked and the accelerator pedal must have been released quickly.

Brake Pressure Support (BPS)
Brake Pressure Support is found on vehicles, without a vacuum pump, between the engine's intake pipe and power brake booster (V8) and compensates poor servo assistance in the event of poor vacuum.
Brake Pressure Support uses the double pressure sensor on the power brake booster and when the pressure difference between the front and rear chambers is too small during braking, the system cuts in.