Hydraulic System: Description and Operation

Hydraulic Brake Actuation
The hydraulic brake actuation system consists of the following components:
^ ABS
^ Brake master cylinder
^ Front disc brake calipers
^ Rear wheel cylinders (gasoline vehicles)
^ Rear disc brake calipers (hybrid vehicles)
^ Brake tubes and hoses
The hydraulic brake system is diagonally split with the LH front and RH rear brakes on one circuit and the RH front and LH rear brakes on the other circuit.

Disc/Drum Brake Actuation (Gasoline Vehicles)
The brake pedal is connected to the brake master cylinder. When the brake pedal is pressed, brake fluid is pushed through the double-walled steel lines and flexible hoses to the rear wheel cylinders and the front disc brake calipers. The brake fluid enters the rear wheel cylinders, forcing the rear wheel cylinder pistons outward against the brake shoes and linings. The brake shoes and linings press against the braking surfaces of the brake drums. The front disc brake caliper pistons are forced outward against the brake pads and linings, and contact the braking surfaces of the front brake disc. When the brake pedal is released, the pressure is relieved, returning the front disc brake caliper pistons and rear wheel cylinder pistons and the brake shoes, brake pads and linings to the unapplied position.

Disc/Disc Brake Actuation (Hybrid Vehicles)
The brake pedal is connected to the brake master cylinder. When the brake pedal is pressed, brake fluid is pushed through the double-walled steel lines and flexible hoses to the rear disc brake calipers and the front disc brake calipers. The brake fluid enters the disc brake calipers, forcing the caliper pistons outward. The rear disc brake caliper pistons are forced outward against the brake pads and linings, and contact the braking surfaces of the rear brake disc. The front disc brake caliper pistons are forced outward against the brake pads and linings, and contact the braking surfaces of the front brake disc. The driver does not, under normal circumstance, have direct control over the amount of brake pressure that is applied to the brake disc. When the brake pedal is released, the pressure is relieved, returning the front disc brake caliper pistons, rear disc brake caliper pistons, and the brake pads and linings to the unapplied position.