6 Parts of a Drum Brake System (and How They Work)
There are two types of brake systems: disc brakes and drum brakes. Almost all new vehicles are equipped with disc brake systems because disc brake systems are more heat resistant and have a better braking effect on the wheels.
The brake drum and brake shoes represent the classic braking system used in older vehicles. However, there are still some vehicles that use drum brake systems today. It is a relatively inexpensive braking system that is suitable for large vehicles such as trucks. What are brake drums and brake shoes? Just as brake shoes are brake pads, brake drums are essentially the same as brake discs. Drum brake systems use brake shoes as brake pads. Brake drums resemble bowls more than flat discs.
Brake drums are attached to each wheel of a vehicle, or there may be drums on the rear wheels only and rotors on the front wheels. The brake shoes press against the rotating surface of the brake drum.
Together, they create the friction needed to slow the vehicle. Sounds pretty simple, right?
The 6 main parts of a drum brake system
1. Brake shoes
As mentioned earlier, brake shoes act as the brake pads in the braking system. They contain brake pads that press against the brake drum to create friction.
This friction slows or stops the vehicle. When installing the brake shoes, you should avoid touching the brake drum. However, you should get as close to them as possible.
2. Brake piston
The brake piston is responsible for forcing the brake shoes into contact with the surface of the brake drum. This occurs after the brake fluid exerts pressure on the piston. If the brake shoes are too far away from the brake drum, they have to push further to reach the brake drum, which puts more stress on the pistons.
3. Brake Cylinders
Each wheel on a drum-brake vehicle has a brake cylinder. The cylinder is usually located on top of the wheel. This allows the piston to push the brake shoes into the brake drum, slowing the vehicle.
4. Emergency Brake Lever
The drum brake system includes an emergency/parking brake, which consists of a lever and a cable. When the driver pulls up on the lever, the brake shoes disengage and the vehicle remains in neutral.
5. Brake Cable
The cable connects the emergency brake lever to the brake shoes of the braking system. This cable is a key component of the emergency braking mechanism, so you need to make sure it continues to function. This puts more strain on the brake drum and brake shoes.
6. Automatic adjusters
When the brake shoes wear too much, they automatically separate from the brake drum because there is less material left on the brake drum. This causes the brake pedal to drop slightly to the floor when you press it. The role of the automatic adjuster is to prevent this from happening.
