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.