Drum brakes are used on the rear of many rear –wheel-drive, front-wheel-drive, and four –wheel-drive vehicles.Since the early 1970s, few vehicles have been manufactured with drum brakes on the front wheels.

Typical drum brake assembly

Drum brakes were the first type of brakes used on motor vehicles, Even today, over 100 years after the first “horseless carriages”, drum brakes are still used on the rear of most vehicles.

Drum brakes use two brake shoes mounted on a stationary backing (back) plate, also called a support plate. Hydraulic force from the master cylinder to the wheel cylinder pushes brake shoes against the rotating drum.

Drum brakes are economical to manufacture, service, and repair. Parts for drum brakes are generally readily available and reasonably priced. On some vehicles, an additional drum brake is used as a parking brake on vehicles equipped with rear disc brakes.

Typical brake system components showing disc brakes on the front and drum brakes on the rear

•  ADVANTAGES AND DISADVANTAGES

Advantages of drum brakes include:

•  Commonly known by many service people.
•  Common parts available.
•  Generally low-cost parts.
•  Few special tools or equipment are required.
•  The special tools that do help are readily available.
•  Parking brake easily used and serviced with drum brakes.

Disadvantages of drum brakes include:

•  Many small and separate parts to check, service, clean, handle, and lubricate.
•  Fades easily when hot. The drum temperature expands the drum away from the lining material.
•  Water reduces braking action because the water gets between the lining and the drum and little friction is possible.