Which part returns the pushrod to its original position when the brake pedal is released?

The function of returning the pushrod to its original position upon brake pedal release is primarily attributed to the return spring. When the brake pedal is depressed, the pushrod is pushed forward to activate the braking system. Upon releasing the brake pedal, the return spring exerts force on the pushrod, pulling it back to its original position. This action is crucial for ensuring that the braking system is disengaged and that the vehicle can roll freely when necessary.

The return spring not only helps to restore the pushrod but also maintains proper spacing within the brake system, preventing any unwanted engagement of the brakes when they're not needed. This mechanism is essential for the safe and efficient operation of hydraulic and mechanical brake systems alike. Other components like the lever, output rod, and spool valve perform different roles in the braking system and do not possess the specific function of returning the pushrod to its starting position.