rear drum brakes bleeder valve

Understanding Rear Drum Brakes and the Importance of the Bleeder Valve

When it comes to automotive braking systems, rear drum brakes are a common sight, particularly in older vehicles and some newer models designed for economy. These systems rely on a different mechanism than the more widespread disc brakes. One of the critical components of rear drum brakes is the bleeder valve, which plays an essential role in maintaining brake performance and safety.

What Are Rear Drum Brakes?

Rear drum brakes utilize a cylindrical drum that rotates with the wheel. Inside this drum, brake shoes expand against the inner surface of the drum when the brake pedal is pressed, creating friction that slows the vehicle down. This design is efficient and has been a standard for many vehicles, particularly those not designed for high-performance driving.

Despite their effectiveness, rear drum brakes can be prone to certain issues, particularly related to fluid and air management. This is where the bleeder valve shines.

The Role of the Bleeder Valve

The bleeder valve, or bleeder screw, is a small valve found on the brake cylinder of drum brakes. Its primary purpose is to allow air and old brake fluid to escape from the brake system during maintenance. Proper brake fluid is vital for reliable braking performance, and over time, moisture can seep into the fluid, leading to boiling points and reduced performance.

During regular brake maintenance, technicians will use the bleeder valve to bleed the brake lines. This process involves opening the valve while someone presses the brake pedal, allowing trapped air and old fluid to escape. This helps improve the overall braking efficiency and ensures that the system is filled with clean, efficient brake fluid.

Neglecting to maintain the bleeder valve can lead to significant braking issues. If air enters the brake lines, you may experience a spongy brake pedal, reduced braking power, or even complete brake failure in severe cases. Regular maintenance checks should include inspecting the bleeder valve for corrosion, damage, or leakage, ensuring that it maintains a tight seal when closed.

Furthermore, it’s essential to replace brake fluid at intervals recommended by the manufacturer, as old fluid can lead to brake fade, where the vehicle's braking power diminishes with repeated use. Bleeding the brake system is an integral part of this maintenance routine.

DIY Brake Maintenance

For those interested in performing their brake maintenance, using the bleeder valve can be done relatively easily with the right tools. You will need

1. Brake fluid Ensure you have the appropriate type for your vehicle. 2. A helper To assist in the process of bleeding the brakes. 3. A catch container To catch any old fluid that escapes during the process.

To bleed the brakes, start at the wheel furthest from the master cylinder, typically the passenger side rear. Here’s a simplified process

1. Attach a clear tube to the bleeder valve and submerge it in the catch container. 2. Open the bleeder valve slightly. 3. Have your helper press the brake pedal several times and hold it down. 4. Close the valve before your helper releases the brake pedal to avoid sucking air back into the system. 5. Repeat the process until you see clear, bubble-free fluid in the tube.

Conclusion

Understanding the function and importance of the bleeder valve in rear drum brake systems is crucial for any vehicle owner. Regular maintenance ensures not only the longevity of your brakes but also the safety of your vehicle. Whether you choose to DIY or consult with a professional, make sure that the brake fluid is healthy and that any trapped air is removed to maintain optimal braking performance.