Braking Without ABS

Braking without ABS

When the brake pedal is depressed, the force of the pedal is transmitted via the air hydraulic brake power assist unit (brake servo) to the master cylinder pistons and the brake light switch triggered. The center valve in the secondary piston and the seal on the primary piston close the connections to the brake fluid reservoir. In cars with TRACS the primary piston also has a center valve.
The hydraulic pressure in the two brake circuits increases and triggers the pistons in the brake calipers which press the brake pads against the brake discs.
When the brake pedal is released and returns to its resting position, the pistons in the master cylinder return to their resting position. The connection to the brake fluid reservoir opens as the center valve, the seals and the braking system are depressurized. The pistons in the brake calipers return to their resting position because of their seals.