Shimano’s BR-R8170 [paid link] hydraulic disc brakes offer cyclists precise control and powerful braking performance. However, to ensure their longevity and optimal performance, proper maintenance is crucial. Regularly bleeding your hydraulic disc brakes is an essential part of keeping them functioning smoothly, ensuring a reliable braking experience every time you ride. In this guide, we’ll take you through the process of bleeding and maintaining your Shimano BR-R8170 [paid link] brakes.
Understanding Shimano BR-R8170 Hydraulic Disc Brakes
The Shimano BR-R8170 [paid link] is part of Shimano’s high-performance hydraulic brake line, designed for road bikes. These brakes feature a hydraulic system that uses brake fluid to transfer pressure from the brake lever to the caliper, which then clamps the brake pads onto the rotor to stop the bike. This system provides smooth, consistent braking power with minimal effort.
Over time, air bubbles or contaminants can enter the hydraulic system, leading to spongy brakes and reduced performance. Regular maintenance, including bleeding the brakes, ensures that the system is free from air and that the brake fluid is in optimal condition.
Tools Required
Before you begin, make sure you have the following tools and materials:
- Shimano Bleed Kit [paid link] (includes syringes, hoses, and fittings)
- Shimano mineral oil [paid link] (specific to Shimano hydraulic systems)
- 7mm and 10mm wrenches
- Torx T10 wrench
- Brake rotor tool (optional)
- Clean cloth or paper towel
- Isopropyl alcohol (for cleaning)
- Protective gloves
Step-by-Step Guide: How to Bleed Shimano BR-R8170 Brakes
1. Prepare Your Bike and Work Area
Start by ensuring that your bike is stable, preferably in a work stand. This will allow you to have better access to the brake components. Make sure the area around the brake caliper and lever is clean, as dirt or debris could contaminate the hydraulic system. It is also recommended to place some protective material on the ground to catch any fluid drips.
2. Remove the Wheel and Brake Pads
For better access to the brake caliper and to avoid contaminating the pads, it’s important to remove the wheel from the bike. You should also remove the brake pads. If you’re not replacing the brake pads, be sure to store them in a clean, safe area. You can use a pad spacer to avoid damaging the pistons while working on the brakes.
3. Set Up the Syringe and Bleed Kit
Shimano’s BR-R8170 brake system uses mineral oil [paid link] for hydraulic braking. First, attach the syringe to the brake lever port using the appropriate fittings from your Shimano bleed kit [paid link]. Attach the second syringe to the caliper port. Before you proceed, ensure both syringes are filled with brake fluid to avoid air contamination in the system.
4. Open the Brake Caliper Port
Using a 10mm wrench, remove the bleed port screw from the brake caliper. Be sure to place the screw in a safe spot, as you will need to reattach it later. Place a clean rag or paper towel around the brake caliper to catch any brake fluid that may spill during the process.
5. Pump Fluid into the System
With both syringes attached, gently push brake fluid from the caliper syringe into the system. This will force any air or old fluid out of the brake system. Be patient and allow the fluid to flow steadily. As the fluid moves through the system, you’ll see any air bubbles rise to the top of the syringe connected to the brake lever. If the fluid looks cloudy or dirty, continue pushing the fluid through until it runs clean.
6. Close the System
Once the brake fluid is clear of air bubbles and contaminants, stop the fluid flow and close the bleed ports. Begin by tightening the port screw on the caliper with the 10mm wrench. Ensure it is snug but not over-tightened. Similarly, secure the port on the brake lever side, ensuring no fluid can escape.
7. Test the Brake Lever
After completing the bleed, check the brake lever feel by squeezing it. It should feel firm and responsive. If the lever feels spongy or doesn’t return to its normal position, there may still be air trapped in the system. In this case, you may need to repeat the bleeding process or inspect the system for leaks.
8. Reinstall the Brake Pads and Wheel
Once you’ve confirmed that the brakes feel firm, carefully reinstall the brake pads. Check that they are positioned correctly and that the rotor spins freely without any interference. Afterward, reinstall the wheel, ensuring that the rotor is aligned with the brake pads.
9. Clean Up and Check for Leaks
Before riding, it’s crucial to clean up any excess brake fluid. Use isopropyl alcohol to wipe down the brake caliper, brake lever, and any areas where fluid may have spilled. Be sure to also check for any leaks around the bleed ports. If you notice any signs of leaking fluid, recheck the connections and ensure the bleed screws are tight.
Ongoing Maintenance Tips for Shimano BR-R8170 Brakes
Regular Fluid Checks
While bleeding your brakes is essential, it’s also important to check the fluid level [paid link] in your hydraulic brake system regularly. If you notice the brake lever becoming soft or if your braking power decreases, it may be time for another bleed or a fluid top-up. Shimano recommends replacing the brake fluid approximately once a year or whenever the brake performance starts to degrade.
Keep the System Clean
Brake performance can degrade if contaminants such as dirt, dust, or moisture enter the hydraulic system. To prevent this, always clean the brake calipers and lever components regularly. When cleaning, be cautious not to get any cleaning chemicals on the brake pads or rotor. Avoid using solvent-based cleaners that could damage the hydraulic seals.
Inspect Brake Pads and Rotors
The brake pads and rotors should be inspected regularly for wear. Over time, pads can wear down and rotors may develop grooves, which can affect braking performance. If you notice any irregularities, replace the components promptly to maintain optimal braking power.
Conclusion
Properly maintaining your Shimano BR-R8170 hydraulic disc brakes is crucial for ensuring maximum braking power and rider safety. By following this step-by-step guide on how to bleed and maintain the system, you can prolong the life of your brakes and keep your bike performing at its best. Regular maintenance not only prevents issues but also improves the overall cycling experience, giving you the confidence to ride safely and efficiently.