How Disc Brakes Works - Part 2 | Autotechlabs

Summary

This video explains the workings of an automotive disc brake system, focusing on the pedal side. It describes the role of the master cylinder in transferring force to the calipers and how it operates with primary and secondary pistons. The video also covers brake boosters, which assist in reducing pedal effort using engine vacuum. By illustrating the components inside the master cylinder and brake booster, the video explains how they work together to ensure effective braking, even under varying conditions. The process simplifies braking, reducing the force required to apply brakes.

Takeaways

• 😀 The master cylinder is a key component in transferring force from the brake pedal to the calipers.
• 😀 The master cylinder contains important parts like inlet ports, compensating ports, primary and secondary pistons, retaining springs, and piston seals.
• 😀 Pressing the brake pedal pushes the push rod, which activates the primary piston, closing the first compensating port and creating pressure in the cylinder.
• 😀 The secondary piston, pushed by the primary piston, closes the second compensating port and sends brake fluid to the calipers.
• 😀 If the secondary piston fails to build pressure, the primary piston can still develop pressure by increasing its travel.
• 😀 If the primary piston fails, the secondary piston cannot move as it won't receive any pressure, resulting in the push rod needing more force to operate.
• 😀 The introduction of brake boosters made braking easier by assisting the brake pedal with engine vacuum, reducing the effort needed to apply the brakes.
• 😀 Brake boosters consist of components like a valve rod, dust boot, air filter, valve spring, diaphragm, diaphragm spring, and vacuum check valve.
• 😀 When the brake pedal is pressed, the valve rod opens the inlet valve, allowing air into the diaphragm's front chamber and creating a vacuum in the rear chamber.
• 😀 The vacuum created in the booster helps pull the diaphragm, pushing the push rod toward the master cylinder, thus easing the braking process.

Q & A

What is the main function of the master cylinder in an automotive braking system?

The master cylinder transfers the force from the brake pedal to the brake calipers, creating hydraulic pressure that activates the brakes.

How does pressing the brake pedal affect the master cylinder?

When the brake pedal is pressed, the push rod moves the primary piston in the master cylinder, which builds pressure and forces fluid into the brake calipers.

What is the role of the secondary piston in the master cylinder?

The secondary piston works alongside the primary piston. It is pushed by the primary piston to further build pressure and direct fluid to the brake calipers.

What happens if the secondary piston fails to build pressure?

If the secondary piston fails, the primary piston can still generate pressure, although it requires increased travel of the brake pedal to do so.

What is the purpose of compensating ports in the master cylinder?

Compensating ports allow fluid to enter and exit the master cylinder, maintaining pressure balance and ensuring proper fluid flow during braking.

Why is the brake booster necessary in modern braking systems?

The brake booster reduces the effort needed to press the brake pedal by using vacuum pressure from the engine, making it easier for the driver to apply the brakes.

How does the brake booster assist in braking?

When the brake pedal is pressed, the brake booster opens a valve that allows air to enter the diaphragm's front chamber. This, combined with vacuum pressure in the rear chamber, pulls the diaphragm, assisting the push rod in transferring force to the master cylinder.

What components make up the brake booster?

The brake booster consists of a valve rod, dust boot, air filter, valve spring, diaphragm, diaphragm spring, vacuum check valve, and hydraulic push rod.

What would happen if the primary piston in the master cylinder fails?

If the primary piston fails, the secondary piston will not receive any pressure, leading to a loss of braking functionality. The brake pedal may need more force to engage the system.

How do the pistons in the master cylinder work together to build pressure?

The primary piston is pushed by the brake pedal, which closes the first compensating port. This creates pressure, which pushes the secondary piston, closing the second compensating port and increasing pressure to the brake calipers.