How to Bleed a Motorcycle Master Cylinder

Written by jeffrey caldwell
  • Share
  • Tweet
  • Share
  • Email

Motorcycles utilise separate master cylinders to operate the front and rear brakes. The front master cylinder will be bolted to the handlebars right beside the front brake lever. The rear master cylinder will be on the side of the motorcycle near the rear brake pedal. These master cylinders operate independently, and each must be bled separately. You should bleed the master cylinder any time you disconnect the hydraulic line from the master cylinder or brake caliper, or if the brake begins to feel spongy.

Skill level:
Easy

Other People Are Reading

Things you need

  • Phillips screwdriver
  • Brake fluid
  • Clear plastic tubing
  • Plastic or glass jar
  • Wrench set

Show MoreHide

Instructions

  1. 1

    Remove the screws that connect the master cylinder cover to the master cylinder reservoir, using a Phillips screwdriver.

  2. 2

    Fill the master cylinder with fresh brake fluid. Do not allow the master cylinder to run dry at any point during this operation.

  3. 3

    Locate the bleeder screw on the front brake caliper.

  4. 4

    Attach a length of clear plastic tubing to the brake bleeder screw. Immerse the other end of the tube in a jar half-filled with brake fluid.

  5. 5

    Have an assistant operate the front brake lever. Squeeze the brake lever a few times and then hold it closed.

  6. 6

    Open the bleeder screw using a wrench. Allow a little fluid to seep out. You will notice air bubbles in the brake fluid. Close the bleeder screw before releasing the brake lever.

  7. 7

    Repeat the process described in the two steps above until there are no more air bubbles in the brake fluid.

  8. 8

    Remove the clear plastic tube from the bleeder screw.

  9. 9

    Drop the master cylinder cover into position over the master cylinder reservoir. Reinstall the two screws that secure the cover.

  1. 1

    Locate the rear master cylinder. It will be near the rear brake pedal.

  2. 2

    Remove the two screws that secure the master cylinder cover to the master cylinder reservoir, using a Phillips screwdriver, and then remove the cover.

  3. 3

    Fill the master cylinder reservoir with fresh brake fluid. Do not allow the master cylinder to run dry at any point in the bleeding process.

  4. 4

    Locate the bleeder screw on the rear brake caliper.

  5. 5

    Attach a length of clear plastic tubing to the bleeder screw. Immerse the other end of the tubing in a jar half-filled with brake fluid.

  6. 6

    Have an assistant operate the rear brake pedal. Pump the rear brake pedal a few times, and then hold the pedal down.

  7. 7

    Open the bleeder screw using a wrench. Allow a little fluid to seep out. You will notice tiny air bubbles in the fluid. Close the bleeder screw before releasing the brake pedal.

  8. 8

    Repeat the two steps described above until there are no more bubbles mixed in with the fluid.

  9. 9

    Remove the plastic tubing from the brake bleeder screw.

  10. 10

    Place the cover over the brake master cylinder. Reinstall the two screws that secure the cover, using a Phillips screwdriver.

Tips and warnings

  • Older and lightweight motorcycles may utilise a mechanical linkage to connect the rear brake pedal to the rear brake. These systems cannot be bled.
  • Brake fluid can strip the paint of metal. Do not allow brake fluid to contact any of the finished surfaces on your motorcycle.

Don't Miss

Resources

Filter:
  • All types
  • Articles
  • Slideshows
  • Videos
Sort:
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the eHow.co.uk site, you consent to the use of cookies. For more information, please see our Cookie policy.