The Brake Drum and Brake Hoses

A brake drum is a metal cylinder attached to a vehicle’s wheel hub. When the brake pedal is pressed, hydraulic pressure forces two long, curved brake shoes against the drum, slowing and stopping the car.

Brake drums can experience many issues over time. They should be inspected periodically for signs of wear or damage.

Brake Shoes

Although rare, some cars use a drum brake in addition to a disc brake on the rear axle. These brakes are used only as emergency or parking brakes. When the brake pedal is pushed, hydraulic pressure generated by a piston inside the wheel cylinder pushes two ends of the brake shoes apart and against the inner drum surface. This creates the necessary friction to slow and stop the car.

The brake shoes are fastened to the brake drum with pins and springs. They have a lining made of organic or metallic compounds that comes in contact with the brake drum and wears down over time.

Brake shoes should be replaced when they start showing signs of wear. This typically manifests as a scraping noise from the inside of the brake drum or a spongy feeling when the brake pedal is depressed. The average brake shoe can last 30,000 miles under normal conditions. This varies considerably between drivers, though, depending on how often the brakes are pressed and depressed.

Brake Linings

Brake linings (friction material) are attached to brake shoes and press against the inside of drums to generate braking force. The friction between the linings and the inside of the drum converts the kinetic energy of the vehicle into heat energy which slows or stops the car.

The linings are made from relatively soft but tough materials such as fiber, sintered metal or cermet, which are then bonded or riveted to a brake shoe. The friction coefficient of these linings is typically high.

Most drum brakes have a wear sensor that produces an annoying squeal or warning signal to warn drivers that the pads are worn and should be replaced. This prevents the lining from wearing to the point that it will contact the brake drum or rotor and cause damage and degraded braking performance. Performing regular brake inspections and replacing the brake linings as recommended will help keep your truck operating at peak performance and minimize costly repairs to other parts of the braking system.

Brake Pads

When you step on the brake pedal, your car's caliper squeezes the brake pads against the rotating rotor (or drum, if you have a traditional drum-style system). The resulting friction converts the kinetic energy of your vehicle-in-motion into thermal energy, or heat. That slows the rotor and axle rotation and brings your car to a stop.

Brake pads come in a variety of materials and styles. The choice depends on the kind of driving you do and the type of vehicle you drive. A passenger car that's used primarily for ferrying kids around will probably require a different set of brake pads than a three-quarter ton truck that's regularly hauling heavy loads over mountainous terrain.

The best brake pads dissipate heat quickly to prevent brake fade. They also produce less dust than other types of brake pads, though they may require a little more actuating force to generate the same level of stopping power.

Brake Hoses

Bringing hydraulic pressure from the master cylinder and proportioning valve to each brake, the brake hoses are the backbone of the car’s braking system. They should be inspected regularly and replaced if they suffer from a loss of pressure or cracking. Ideally, you can test them by having someone pump the brake pedal and looking for bubbles or blisters. Cracking in the middle of the hose will also cause a spongy brake pedal feel and is definitely something to be avoided.

The main reason for hose failure is the same as for any rubber component that experiences prolonged exposure to sun and heat – oxidation that weakens the material. Braided stainless steel lines are much more resistant to this deterioration, hence they’re used by many performance cars.

They also tend to be less prone to bulging than rubber hoses too. However, they are usually more expensive. If you’re unsure what to do when replacing your brake hoses, it’s best to visit a garage and have them checked by an expert.