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How to Bleed Shimano Hydraulic Disc Brakes

The hydraulic disc brakes on your mountain bike are awesome at providing stopping power, however, they do need some occasional maintenance to keep them running well. Bleeding the brakes on your bike removes any air bubbles from the brake lines, keeping your brakes feeling firm and working well. Shimano has made bleeding their disc brakes quite easy with the right tools and parts. So, grab your Shimano bleed kit, and follow along to have your brakes feeling like new.


How to Bleed Shimano Disc Brakes

  1. Remove the rear wheel.

  2. Remove the brake pads. Your Shimano brake pads will be secured by a cotter pin or bolt, depending on your brake type. Use pliers for a cotter pin, or the 3 mm allen wrench for a bolt in order to remove the pads.

  3. Install the Bleed Block using the cotter pin or bolt.

  4. Adjust the brake lever so it is level. This helps the air bubbles rise to the top.

  5. Remove the bleed fitting screw with the 2.5 mm allen wrench.

  6. Thread in the Shimano brake bleed funnel and leave the plunger in.

  7. Fill the syringe with Shimano hydraulic mineral oil and place the syringe on the bleed nipple.

  8. Open the bleed fitting using the 7 mm box wrench.

  9. Remove the plunger from the Shimano bleed funnel and begin pushing fluid through the system.

  10. Close off the bleed fitting and remove the syringe. Add a bit of suction to the syringe to avoid splashing any hydraulic fluid on your Shimano brakes.

  11. Remove remaining air bubbles by alternating beteween full pulls and light flicks on the brake lever.

  12. Replace the plunger and remove the funnel.

  13. Replace the bleed fitting screws (or caps) at both the lever and caliper sides.

  14. Clean brake lever and caliper with isopropyl alcohol using a rag.

  15. Remove the Shimano brake bleed block and re-install brake pads with the cotter pin or bolt.

  16. Re-install rear wheel.

  17. Repeat the process for the front wheel if needed.

Voila! Your Shimano brakes are now bled and ready to shred!

Tools Required To Bleed Shimano Disc Brakes

  • Syringe
  • Shimano Hydraulic Mineral Oil
  • Isopropyl Alcohol
  • Shimano Bleed Funnel
  • 2.5 mm Allen Wrench
  • 3 mm Allen Wrench or Pliers, depending on brake style.
  • 4 mm Allen Wrench
  • 5 mm Allen Wrench
  • 7 mm Box Wrench
  • Bleed Block

How Often do you Need to Bleed Shimano Hydraulic Disc Brakes?

Depending on how often and how far you ride, you will need to bleed your Shimano hydraulic disc brakes about every six months. Some telltale signs that the brakes on your bike need to be bled are that they feel squishy, or that you have to pull the lever almost all the way to the handlebars before they work. Bleeding your brakes will return braking power and precision. If bleeding does not fix these issues, you may need to replace your brake pads or rotors.

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