Symptoms Of Failing Brake Drums

Brake drum issues can show up in several ways. It might be time for a brake service if any of these symptoms pop up:

1. Scraping Noises

When the friction material (also called the brake lining) on your brake shoes wears down, the backing plate of the shoe will start to grind against the brake drum. This produces a grinding or scraping noise when you brake. 

If unremedied, the worn brake shoes can damage the surface of the brake drum, just like a worn brake pad can damage a brake rotor.

2. Low Brake Pedal

Does it feel like that brake pedal has to travel lower than usual when you brake?

Worn brake drums create excess clearance between the brake drum and the brake shoes. So each shoe has to travel further to push against the brake drum.

This also applies if you have worn brake shoes in your drum brake system. The thinned friction material on your drum brake shoes will result in a low brake pedal.

3. Pulsating Brakes

Brake drums wear out just like the brake rotor in disc brakes. Sometimes they wear out unevenly.

The uneven surface of the brake drum will reflect as vibrations or pulsations in your brake pedal. This is similar to pedal vibrations caused by a warped or uneven rotor in disc brakes.

There is an exception.

If you’re making an emergency stop with a vehicle fitted with Anti-Lock Braking System (ABS), the vibration is likely the ABS actuating to help you brake safely.

Otherwise, brake pedal pulsations are a sign to visit the mechanic for a brake repair. 

4. Parking Brake Failure

The parking brake relies on brake shoe pressure against the brake drum to keep the vehicle stationary, especially when parking on a slope.

Parking brakes are often installed on the rear wheel, in rear drum brakes (or rear disc brakes if your car uses all-disc brake assembly).

So, if there are issues with the rear drums or rear brake shoe pairs, the parking brake will feel loose when you engage it. Your vehicle might slip even with the parking brake lever locked on.

5. Soft Brake Feel

When the brake lining or drum is worn down, your vehicle will take longer than usual to stop. That’s because there’s less friction going on when you press the brake pedal, making the brakes work harder.

This is often an indicator that the brake shoes and brake drum need replacing if your car has drum brakes. The same applies if your vehicle has disc brakes — it’s usually a sign of worn brake pads and brake rotor (brake disc).

In either case, that would be the time to get hold of some auto repair expertise to help fix your braking system.

How Much Does A Brake Drum Replacement Cost?

The average cost for replacing a bad brake drum falls between $232 to $261. 

This breaks down to:

• Labor costs estimated at  $58-$73 
• Brake components priced between $174-$188

The estimate for this brake repair doesn’t include fees and taxes, and doesn’t factor in specific vehicle make or location. Additional repairs may also be required that may increase the final cost.

How Urgent Is A Brake Drum Replacement?

It’s unsafe to drive with a vehicle experiencing brake system issues, even if the problem may only appear to be a bad brake drum on a set of rear brakes.

The best thing you can do is get your brake system checked by an auto repair professional and have a brake job done if necessary.

5 Brake Drum Replacement FAQs

Let’s get to know drum brakes and the brake drum a little better:

1. What Is A Brake Drum?

Brake drums are components in a drum brake system. The brake drum is a metal drum, typically cast iron or aluminum, bolted to the wheel hub and rotates with it.

How does it work?

A brake wheel cylinder and a pair of brake shoes are mounted onto the drum brake backing plate, inside the brake drum.

When you engage the brakes, the wheel cylinder pistons push the brake shoes against the brake drum, generating friction to stop the car. This is slightly different from disc brakes, where brake pads squeeze a brake rotor to stop the wheel.

The drum brake is generally found on the rear wheel (with disc brakes on the front wheels) and typically doubles as the vehicle’s parking brake. This is why drum brakes are often referred to as the rear drum brake, and the brake shoe is a rear shoe. 

2. How Are Brake Drum Issues Diagnosed?

An auto repair technician will inspect the brake drum for stress fractures, deep grooves, black spots (hot spots), or a blue tint that indicates the brake drum has exceeded its allowable heat range.

If any of these exist, the technician may recommend machining the drum (to resurface it) or a complete brake drum replacement.

3. How Often Should Brake Drums Be Replaced?

The brake drum is often replaced simultaneously with drum brake shoes. This is typically between 30,000-60,000 miles. However, that number largely depends on driving conditions and habits.

Being in frequent start-and-go traffic or aggressive brake usage will definitely wear down the brake shoes and drum faster.

Driving in mountainous terrain will also cause more wear to your brake components. So, make sure to get regular brake service at your mechanic or dealership to keep your brake system in shape.

4. Are Drum Brakes Difficult To Replace? 

Replacing the rear drum brake isn’t necessarily difficult, and often only needs a basic set of hand tools and a brake adjuster tool.

However, it does involve a lot of brake components and requires a significant amount of labor.

Drum brakes have several small brake parts (like return springs) that can quickly cause confusion if you’re not sure where they go. Even brake shoe mounting has to be positioned specifically as one brake shoe is often longer than the other.

So, if a DIY sounds like too much trouble, always get a professional to handle it instead.

5. How Do I Replace Drum Brakes? (A General How-To)

Here’s an overview of a drum brake replacement. This isn’t a specific step-by-step guide, but a general “how-to”:

• Jack up the vehicle and ensure it’s safely secured with jack stands.

• Loosen the lug nuts, and remove the wheel and tire assembly to expose the brake drum.

• Detach the brake drum from the wheel hub. 

Note: Brake drums can be difficult to remove if they haven’t been serviced for a while. In this case, the rust must be loosened so the drum can be pried or hammered off.

• With the brake drum removed, inspect the brake shoes, wheel cylinder, springs, and the parking brake mechanism.

• Clean the brake assembly of brake dust, debris, or brake fluid. A brake cleaner comes in handy here.

• Install the new brake drum and brake shoes onto the backing plate. Anytime brake drums are replaced, new brake shoes are required.

• Use the brake adjuster to adjust the new shoe distance from the new drum.

• Reattach the tire back on and lower the vehicle to the ground.

There’s a lot more detail involved during a drum brake replacement, but hopefully, this overview gives you an idea of what happens.