what needs to be replaced on drum brakes

What Needs to Be Replaced on Drum Brakes?

Drum brakes are a crucial part of many vehicles, providing reliable stopping power through a design that has been used for decades. While modern vehicles increasingly favor disc brakes, drum brakes remain common, especially in older models and on the rear axles of some newer vehicles. Like any braking system, drum brakes wear out and require maintenance to ensure they function properly. Understanding what needs to be replaced on drum brakes can help vehicle owners maintain their braking system effectively and ensure safety on the road.

Key Components of Drum Brakes

Before delving into what needs replacement, it’s essential to understand the main components of a drum brake system. Drum brakes consist of several parts including the brake drum itself, brake shoes, wheel cylinders, return springs, and parking brake components. Each of these components plays a vital role in the braking process, with the brake drum serving as the rotating component that slows the wheel down when the brake shoes are pushed against its inner surface.

One of the most common components that need replacement on drum brakes is the brake shoes. Brake shoes are the friction material that presses against the drum to create the friction necessary for stopping. Over time, the lining material on the brake shoes wears down due to repeated contact with the drum, resulting in reduced braking efficiency. Signs that brake shoes need replacement include a squeaking noise, reduced stopping power, or a warning light on the dashboard. Generally, brake shoes should be inspected and, if necessary, replaced every 30,000 to 70,000 miles, depending on driving conditions and habits.

Brake Drum

The brake drum itself may also require replacement if it becomes worn or damaged. Over time, the surface of the drum can become scored, cracked, or warped due to heat and friction. While some drums can be resurfaced to extend their life, there is a limit to how much material can be removed before they become unsafe. A general rule of thumb is that if the drum’s inside diameter exceeds the manufacturer's specifications, it should be replaced. Additionally, if there are physical signs of damage, such as deep grooves or cracks, replacement is essential.

Wheel Cylinders

Wheel cylinders are hydraulic components that push the brake shoes outward against the drum when the brake pedal is pressed. If a wheel cylinder leaks or fails, it can lead to a loss of braking power on that wheel. Symptoms of a failing wheel cylinder include fluid leaks near the wheel, a spongy brake pedal, or uneven braking. If any of these signs are present, it is advisable to inspect the wheel cylinders and replace them if necessary.

Return Springs and Hardware

Return springs and other hardware components, such as retaining clips and adjusters, are often overlooked but critical for the proper functioning of drum brakes. The return springs ensure that the brake shoes retract when the brake pedal is released, preventing constant contact with the drum. Over time, these springs can weaken or break, leading to poor braking performance and increased wear on brake shoes. Regular inspection and replacement of return springs and hardware can enhance the lifespan and efficiency of the entire braking system.

Conclusion

Maintaining drum brakes is vital for vehicle safety and performance. Regular inspection of brake shoes, drums, wheel cylinders, and associated hardware should be part of any vehicle maintenance routine. By recognizing the signs of wear and knowing when to replace these components, vehicle owners can ensure their drum brakes operate effectively, ultimately enhancing safety on the road. If unsure about any aspect of brake maintenance, it is always prudent to consult a professional mechanic.