Disc Brake working principle, Advantages and disadvantages of Diac Brake – Automobile Study material

Disc type brake

In New model vehicles disc type brake is widely used apart from drum type brake system. In this type of brake system a circular brake disc
as shown in Figure is used instead of
brake drum. Moreover instead of brake shoe flat friction grip is used in this system. When the brake pedal is
pressed by the driver, the simple hydraulic pressure actuates the compressed brake fluid and moves the two pistons towards the caliper assembly. Hence the friction
pad next to the pistons is moved inward and presses the revolving disc located in between them. Therefore, the wheel hub and wheel which is connected to the disc is stopped from rotation. When the driver releases the brake pedal, the pressure on the pistons inside the caliper assembly is
reduced. Hence the piston moves back and the friction pad is released from the disc and releases the brake on the brake disc. Similar to the drum brake, there is a bleeder screw provided in the caliper assembly in a disc brake

Advantages in disc brake

1. Lower weight in construction than
other brakes.
2. Brake force is very high.3. It is sufficient to give low pressure on a brake pedal by the driver.
4. Has less components and hence it can be easily assembled and dismantled.
5. The brake efficiency is not affected
even if the vehicle goes in the water.
6. Testing and maintenance are simple.
7. As the disc is exposed to the ventilated air the heat can be immediately transfer to the atmosphere.


1. As compared to normal brake shoes and linings the wear occurring in the brake pad of the disc brake is very quick.
2. It is essential to use servo unit because of more amount of hydraulic force is required to stop the vehicle.
3. If the disc brake is fitted to the rear
wheels, then hand brake system is
essential as the additional requirement.
4. This system cannot be efficient for
heavy vehicle applications.

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