How to Bleed and Maintain Your Shimano BR-R8070 Hydraulic Disc Brakes

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Hydraulic disc brakes, such as the Shimano BR-R8070 [paid link], are a popular choice for road cyclists due to their superior stopping power and consistency in all conditions. However, like any precision braking system, they require regular maintenance to ensure optimal performance. One of the most essential aspects of maintaining hydraulic disc brakes is proper bleeding, which involves removing air from the brake lines to restore full braking power. In this guide, we’ll walk you through how to bleed your Shimano BR-R8070 [paid link] hydraulic disc brakes and provide tips on how to maintain them for long-lasting performance.

Tools Required

  • Shimano Bleed Kit [paid link] (including bleed syringe and adapter)
  • 5mm and 2mm hex wrenches
  • Torque wrench [paid link]
  • Isopropyl alcohol (at least 90% concentration)
  • Clean rags or paper towels
  • Bleed block (for caliper)
  • Shimano mineral oil [paid link] (for brake fluid)
  • Plastic gloves
  • Small container for catching fluid
  • Phillips screwdriver (for caliper bolt)

Understanding Hydraulic Brake Bleeding

Bleeding hydraulic brakes is necessary when the brake lever feels soft or spongy, or when you notice decreased braking performance. Over time, air can enter the brake lines, causing the hydraulic fluid to become less effective. Bleeding removes the trapped air and replenishes the brake fluid, restoring the responsiveness and reliability of your Shimano BR-R8070 [paid link] hydraulic disc brakes.

Preparation: Gathering the Tools and Setting Up the Workspace

Before starting, ensure you have all the necessary tools at hand. You should also set up a clean, well-lit workspace to avoid contamination of your brake components. Cleanliness is critical during brake maintenance to prevent dirt and debris from entering the brake system, which could cause damage or improper functioning.

Make sure the bike is securely mounted on a stand or resting upright. Having the bike stable ensures that you can work more effectively and avoid any accidental spills of brake fluid.

Step-by-Step Guide to Bleeding Shimano BR-R8070 Hydraulic Disc Brakes

Step 1: Remove the Wheel and Install the Bleed Block

To begin, remove the front or rear wheel to access the brake caliper. Installing a bleed block in the caliper helps prevent the brake pistons from pushing out during the bleeding process. The block is inserted between the brake pads, simulating the position of the rotor.

Step 2: Attach the Bleed Syringe to the Caliper

Using the Shimano bleed kit [paid link], attach the appropriate adapter to the caliper’s bleed port. Insert the syringe filled with Shimano mineral oil [paid link] into the adapter, and ensure it is securely connected to prevent leakage.

Step 3: Open the Bleed Valve

Next, use a 2mm hex wrench to loosen the bleed valve on the caliper. Be sure to do this gently, as over-tightening the valve can cause damage to the threads. Leave the valve slightly open so that the brake fluid can flow freely during the process.

Step 4: Begin the Bleeding Process

Slowly push the mineral oil [paid link] from the syringe into the brake system. Watch for bubbles in the oil, which indicate the presence of air in the brake lines. As the oil flows through the system, air will be forced out, and the fluid will eventually start flowing smoothly without any bubbles.

You should continue this process until only clean, bubble-free brake fluid exits the caliper. This might take several syringes of fluid, depending on how much air is in the system. Keep an eye on the brake fluid level [paid link] in the syringe and top it up if necessary to avoid introducing more air into the system.

Step 5: Close the Bleed Valve

Once all the air has been removed and only clear brake fluid is visible, tighten the bleed valve with a 2mm hex wrench to close it securely. Ensure that the valve is tightened to the manufacturer’s recommended torque setting to avoid leaks during use.

Step 6: Remove the Bleed Syringe and Reinstall the Wheel

Once the bleed valve is closed, remove the bleed syringe from the caliper. Wipe any excess brake fluid from the caliper using a clean rag. Be cautious, as brake fluid can damage paint and other surfaces. Next, reinstall the wheel and check that the brake pads are aligned with the rotor.

Step 7: Test the Brake Lever

Before taking the bike out for a ride, squeeze the brake lever to check the feel of the brakes. If the lever feels firm and responsive, you’ve successfully completed the bleeding process. If the lever feels soft or spongy, you may need to repeat the procedure or check for any additional air in the system.

Maintaining Your Shimano BR-R8070 Hydraulic Disc Brakes

Regular maintenance is key to keeping your Shimano BR-R8070 hydraulic disc brakes performing at their best. Here are some tips to maintain the system and avoid common issues:

1. Regular Brake Fluid Checks

Shimano’s hydraulic disc brakes use mineral oil [paid link], which should be replaced periodically to ensure optimal performance. Depending on the frequency of use and riding conditions, check the brake fluid level [paid link] and top it off if necessary. If the brake fluid becomes dark or discolored, it’s time for a complete fluid change and bleeding.

2. Inspect Brake Pads and Rotors

Inspect the brake pads regularly for wear. If the pads are worn down to the indicator lines, replace them to maintain maximum braking efficiency. Also, check the rotors for any damage, such as cracks or warping. If the rotors are warped, you may need to replace them for improved braking performance.

3. Clean the Brake Components

Cleaning your brake components regularly will prevent dirt and grime buildup, which can affect performance. Use a mild soap solution and a soft cloth to wipe down the brake calipers, rotors, and pads. Avoid using strong solvents or brake cleaners, as these can damage the components.

4. Monitor Brake Lever Feel

If you notice that the brake lever feels soft or spongy, it’s an indication that air may have entered the brake lines. In this case, you should perform a brake bleed to remove the air and restore proper braking performance.

Troubleshooting Common Issues with Shimano BR-R8070 Brakes

1. Spongy Brake Lever

If your brake lever feels spongy, it likely means that there is air in the hydraulic system. This can happen after a brake pad replacement or due to wear over time. Bleeding the brakes will remove the air and restore proper braking performance.

2. Noisy Brakes

Noisy brakes can be caused by contaminants on the brake pads or rotors, misaligned brake pads, or uneven rotor wear. Cleaning the components and ensuring proper alignment of the brake pads with the rotor can help eliminate unwanted noise.

3. Reduced Braking Power

If you notice a reduction in braking power, it could be due to worn brake pads, low brake fluid, or air in the brake lines. Inspecting the brake pads and performing a brake bleed are the first steps in restoring full braking power.

Conclusion

Maintaining your Shimano BR-R8070 hydraulic disc brakes is essential for safe and effective cycling. Regular brake bleeding and fluid maintenance will keep your braking system functioning at its peak. By following the steps outlined in this guide, you can ensure that your brakes deliver reliable, consistent stopping power for many rides to come. Remember to regularly check for air in the lines, inspect the brake pads and rotors, and clean the components to prevent unnecessary wear and tear.