Shimano’s BR-R9170 [paid link] hydraulic disc brakes are known for their precision and reliable stopping power, but like any mechanical component, they require periodic maintenance to perform at their best. One of the most critical maintenance tasks for these brakes is bleeding, which ensures the hydraulic system remains free from air bubbles and that the brake fluid stays at the optimal level [paid link]. In this guide, we’ll walk you through the steps of bleeding your Shimano BR-R9170 [paid link] hydraulic disc brakes, as well as provide maintenance tips to keep them performing at their best.
Tools Required
- Shimano Brake Bleed Kit [paid link] (includes bleed blocks, syringes, and fluid)
- 5mm and 8mm wrenches
- T10 or T15 Torx driver (depending on your brake caliper)
- Isopropyl alcohol (for cleaning)
- Shimano mineral oil [paid link] (specific to the BR-R9170 [paid link] model)
- Clean rags
- Gloves (to prevent skin contact with brake fluid)
Bleeding the Shimano BR-R9170 Hydraulic Disc Brakes
Step 1: Prepare Your Work Area
Start by setting up a clean and well-lit workspace. Make sure you have all the necessary tools within reach and that the bike is stable, preferably in a work stand. If you don’t have a work stand, make sure the bike is in a position where the brake levers are easily accessible and the wheels are not in the way.
Step 2: Remove the Wheel and Install the Bleed Blocks
Before you begin bleeding the brakes, remove the wheel to allow access to the brake caliper. Place the Shimano bleed blocks into the caliper to prevent the pistons from popping out during the process. These blocks will also help keep the brake pads in place and prevent damage.
Step 3: Prepare the Syringe and Brake Fluid
Attach the provided syringe to the brake lever’s hydraulic port. Fill the syringe with the Shimano mineral oil [paid link] specified for the BR-R9170. If you’re unsure of the correct fluid, always refer to the Shimano manual for your specific model to avoid compatibility issues. It’s also a good idea to have some extra fluid on hand in case of any spills during the process.
Step 4: Open the Bleed Port
Locate the brake lever’s bleed port and use the appropriate Torx driver to open it. Be sure not to overtighten the port during reassembly. Once the port is open, connect the syringe to the lever and prepare to start the bleeding procedure.
Step 5: Pump the Brake Lever
With the syringe connected, begin gently squeezing the brake lever to push fluid through the hydraulic system. You may need to use moderate pressure, but it should not be excessive. Keep an eye on the syringe to ensure it is filling with fluid, and watch for air bubbles being flushed from the system.
Step 6: Check for Air Bubbles
As you continue to pump the brake lever, air bubbles will rise through the syringe. Continue pumping until no more air is visible in the fluid line. This may take a few minutes to ensure that all air has been purged. Air bubbles in the hydraulic system can cause spongy brakes, so it’s essential to remove every last one.
Step 7: Close the Bleed Port
Once the fluid is free of air bubbles, carefully tighten the bleed port screw on the brake lever using the Torx driver. Be sure not to overtighten, as this could damage the port or threads. After sealing the port, remove the syringe and wipe any excess fluid from the lever.
Step 8: Reassemble and Test the Brake
Once you’ve completed the bleeding process, reinstall the wheel and remove the bleed blocks from the caliper. With the wheel back in place, check the brake lever feel. It should feel firm with no sponginess. If the lever still feels soft, you may need to repeat the bleeding process to remove any remaining air.
Step 9: Clean Up
After the brake has been bled and tested, make sure to clean up any excess fluid. Brake fluid can be damaging to paint and components, so it’s crucial to wipe away any spills with a clean rag and some isopropyl alcohol. Dispose of any used syringes and rags responsibly.
Maintaining Your Shimano BR-R9170 Hydraulic Disc Brakes
Bleeding is just one part of maintaining your Shimano BR-R9170 brakes. Regular maintenance will ensure that your system operates efficiently and that the braking power remains consistent.
Inspecting the Brake Pads and Calipers
It’s essential to periodically check the brake pads for wear. If the pads are excessively worn, replace them with Shimano-approved pads to maintain performance. Additionally, inspect the calipers for any signs of leaks or damage. Ensure that the pistons are moving freely and that the caliper is aligned properly with the rotor.
Monitoring Brake Fluid Levels
Keep an eye on your brake fluid levels. If you notice any sudden loss of brake performance, this could be a sign that the brake fluid is low. Top up the fluid as needed, and if the levels continue to drop, check for leaks in the system.
Cleaning the Brake Rotors
Brake rotors can accumulate dirt, oil, and grime, which can affect braking performance. To clean the rotors, use isopropyl alcohol and a clean rag. Avoid using harsh chemicals that could damage the rotor surface. Clean the rotor after every ride if you’re riding in wet or muddy conditions.
Keeping the Hydraulic System Free of Contaminants
When working with hydraulic disc brakes, it’s crucial to avoid getting contaminants like dirt, water, or oils into the hydraulic system. Always use clean tools and gloves when handling brake fluid or opening the system. Regularly inspect the system for leaks, and address any issues immediately to prevent further damage.
Checking Brake Lever Feel and Adjustments
The brake lever should feel firm and responsive after bleeding. If the lever is too soft, it could be a sign that air is still in the system, and you may need to repeat the bleeding process. Conversely, if the lever is too hard, it may indicate an issue with the brake pads or the hydraulic system.
Rotating and Re-aligning the Brake Caliper
Over time, the brake caliper may shift slightly from its optimal position, which can lead to inconsistent braking performance. Ensure the caliper is correctly aligned with the rotor and that the pads are evenly spaced. If the caliper is misaligned, loosen the mounting bolts and adjust it to center over the rotor, then retighten the bolts.
Conclusion
Bleeding and maintaining your Shimano BR-R9170 hydraulic disc brakes is a crucial part of ensuring their longevity and performance. By following the correct procedure for bleeding and performing regular maintenance checks, you can maximize your braking efficiency, ensure smooth performance, and ride with confidence. Always use the correct Shimano mineral oil [paid link] and make sure the system remains free from air bubbles, dirt, and contaminants. Regular care and attention will help keep your Shimano BR-R9170 brakes performing at their peak, ride after ride.