How to Bleed and Maintain Your Shimano SM-RT800 Hydraulic Disc Brakes

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Hydraulic disc brakes are a crucial component of your road bike, providing reliable and consistent stopping power. The Shimano SM-RT800 [paid link] is a high-performance rotor designed to work seamlessly with Shimano’s hydraulic disc brake systems. However, to keep your braking system performing at its best, it is essential to regularly bleed and maintain your SM-RT800 [paid link] brakes. In this guide, we will walk you through the process of bleeding your Shimano SM-RT800 [paid link] hydraulic disc brakes and discuss key maintenance practices to keep your braking system in top shape.

Tools Required

To bleed and maintain your Shimano SM-RT800 hydraulic disc brakes, you will need the following tools:

Preparing for the Brake Bleed

Before beginning the brake bleed process, it’s important to prepare both your bike and your work area:

1. Secure Your Bike

Ensure your bike is on a stable work stand so that you can easily access the brake calipers and levers. It’s essential that the bike remains upright during the entire bleeding process.

2. Check Brake Fluid Levels

If your hydraulic brake system is performing poorly, such as having spongy lever feel or inconsistent braking power, the fluid level [paid link] might be low. If this is the case, you will need to replace the brake fluid by bleeding the brakes.

3. Remove the Wheel

Take off the wheel to give yourself clear access to the brake rotor and caliper. Be sure to place it somewhere safe to avoid damage.

4. Clean the Brake Area

Using isopropyl alcohol and a lint-free cloth, clean the brake calipers, rotor, and surrounding area. This ensures that no dirt or contaminants enter the hydraulic system during the bleed process.

Step-by-Step Brake Bleed Process

1. Attach the Syringe to the Brake Caliper

Start by attaching the syringe (filled with Shimano mineral oil [paid link]) to the brake caliper’s bleed port. Be sure to secure the syringe to the port tightly to prevent leaks.

2. Position the Brake Lever

Place the brake lever in a position where you can easily access it. The lever should be squeezed gently to create pressure within the system.

3. Open the Bleed Port

Using a 5mm Allen wrench [paid link], remove the bleed screw on the caliper. This will allow the oil to flow freely during the bleed process. Make sure you keep the screw in a safe place so it doesn’t get lost.

4. Force Fluid into the Caliper

Slowly push the syringe plunger to force mineral oil [paid link] into the brake caliper. As the oil flows, air bubbles will be forced out of the system. Continue this process until the fluid flows consistently and without bubbles.

5. Close the Bleed Port

Once you’re sure that no more air bubbles are present in the oil flow, use a 5mm Allen wrench [paid link] to close the bleed port tightly. This will prevent the oil from leaking and ensure the system is sealed.

6. Check the Brake Lever Feel

Squeeze the brake lever several times to check for a firm and consistent feel. If the lever feels spongy, you may need to repeat the bleed process to fully remove any trapped air.

7. Replace the Bleed Block

Place a brake bleed block inside the caliper to hold the pistons in place and prevent them from inadvertently touching the rotor during the rest of the procedure.

8. Clean Up

Wipe off any excess oil using a clean, lint-free cloth. Dispose of any used brake fluid in an appropriate manner, and clean up any areas where brake fluid has spilled.

9. Reinstall the Wheel

Once the brake bleed process is complete and the system is sealed, reinstall the wheel on your bike, ensuring the rotor is correctly aligned with the caliper.

10. Test the Brakes

Before heading out on the road, perform a few tests by gently applying pressure to the brake lever. This will help ensure that the brake system is functioning properly.

Maintaining Your Shimano SM-RT800 Hydraulic Disc Brakes

Regular maintenance is key to ensuring that your Shimano SM-RT800 hydraulic disc brakes provide reliable stopping power over time. Below are a few essential maintenance tips:

1. Monitor Fluid Levels

Keep an eye on the brake fluid levels. If you notice that the brake lever feels soft or the braking power is reduced, it might be time for another bleed.

2. Inspect Brake Pads

Inspect your brake pads regularly to ensure they are not excessively worn. Replace the brake pads if they are nearing their wear limit to prevent damage to the rotor.

3. Clean the Rotors

To maintain braking performance, clean the brake rotors after every ride, especially if you’ve been riding in wet or muddy conditions. Use a brake cleaner or isopropyl alcohol to remove dirt, grease, and debris from the rotor surface.

4. Check Rotor Alignment

Ensure that the brake rotor is straight and properly aligned with the caliper. If you notice any warping or misalignment, carefully straighten the rotor using a rotor truing tool.

5. Bleed the Brakes Regularly

While it’s not necessary to bleed the brakes after every ride, performing a brake bleed every few months will help maintain optimal performance. This is especially important if you notice air in the system or poor brake lever feel.

6. Lubricate Brake Components

Apply a small amount of lubricant to the brake lever pivot points to ensure smooth operation. Be sure to avoid getting lubricant on the rotor or pads.

Troubleshooting Shimano SM-RT800 Hydraulic Disc Brake Issues

If your Shimano SM-RT800 hydraulic disc brakes are not performing as expected, here are some common issues and troubleshooting steps:

1. Spongy Brake Lever

A spongy lever feel is usually caused by air trapped in the hydraulic system. To resolve this, perform a brake bleed to remove the air bubbles.

2. Inconsistent Braking Power

If you notice inconsistent braking, check the brake pads for wear and ensure that they are properly aligned with the rotor. If necessary, adjust the caliper or replace the pads.

3. Noisy Brakes

If your brakes make squealing or grinding noises, this could indicate dirty or contaminated brake pads or rotors. Clean the rotors and replace the pads if necessary.

4. Brake Pads Dragging

Brake pads may drag if the caliper is misaligned with the rotor. Check the alignment and adjust the caliper if needed to ensure there’s proper clearance between the pads and rotor.

Conclusion

Proper maintenance and bleeding are essential to keeping your Shimano SM-RT800 hydraulic disc brakes functioning at their best. Regularly checking fluid levels, cleaning components, and performing occasional brake bleeds will help ensure smooth and consistent braking power. With these simple steps, you can maximize the performance and longevity of your SM-RT800 brakes and enjoy safe, reliable rides.