Kawasaki Ninja Service Manual: Brake Line Bleeding

The brake fluid has a very low compression coefficient so that almost all the movement of the brake lever or pedal is transmitted directly to the caliper for braking action. Air, however, is easily compressed. When air enters the brake lines, brake lever or pedal movement will be partially used in compressing the air. This will make the lever or pedal feel spongy, and there will be a loss in braking power.

NOTE

The procedure to bleed the front brake line is as follows.

Bleeding the rear brake line is the same as for the front brake.

• Remove: Screw [A] Stopper [B] Front Brake Reservoir Cap [C] Diaphragm Plate Diaphragm
• Fill the reservoir with fresh brake fluid to the upper level line in the reservoir.
• Slowly pump the brake lever several times until no air bubbles can be seen rising up through the fluid from the holes at the bottom of the reservoir.

• Open the rubber cap [A] on the front master cylinder.
• Attach a clear plastic hose [B] to the bleed valve, and run the other end of the hose into a container.

• Bleed the brake line and the master cylinder.

Repeat this operation until no more air can be seen coming out into the plastic hose.

1. Pump the brake lever until it becomes hard, and apply the brake and hold it [A].

2. Quickly open and close [B] the bleed valve while holding the brake applied.

3. Release the brake [C].

NOTE

The fluid level must be checked often during the bleeding operation and replenished with fresh brake fluid as necessary. If the fluid in the reservoir runs completely out any time during bleeding, the bleeding operation must be done over again from the beginning since air will have entered the line.

• Remove the clear plastic hose.
• Tighten the bleed valve, and install the rubber cap.

  Torque - Front Master Cylinder Bleed Valve: 5.4 N·m (0.55 kgf·m, 48 in·lb)

• Remove the rubber cap [A] from the bleed valve on the caliper.
• Attach a clear plastic hose [B] to the bleed valve, and run the other end of the hose into a container.

• Bleed the brake line and the caliper.

Repeat this operation until no more air can be seen coming out into the plastic hose.

1. Pump the brake lever until it becomes hard, and apply the brake and hold it [A].

2. Quickly open and close [B] the bleed valve while holding the brake applied.

3. Release the brake [C].

NOTE

• The fluid level must be checked often during the bleeding operation and replenished with fresh brake fluid as necessary. If the fluid in the reservoir runs completely out any time during bleeding, the bleeding operation must be done over again from the beginning since air will have entered the line.
• Tap the brake hose lightly from the caliper to the reservoir for more complete bleeding.
• Front Brake: First bleeding the right caliper then repeat the above steps for the left caliper.
• Remove the clear plastic hose.
• Install: Diaphragm Diaphragm Plate Front Brake Reservoir Cap
• Follow the procedure below to install the front/rear brake fluid reservoir cap correctly.

First, tighten the brake fluid reservoir cap [B] clockwise [C] by hand until slight resistance is felt indicating that the cap is seated on the reservoir body, then tighten the cap an additional 1/6 turn [D] while holding the brake fluid reservoir body [A].

• Install the stopper and screw.
• Tighten: Torque - Front Brake Reservoir Cap Stopper Screw: 1.2 N·m (0.12 kgf·m, 11 in·lb)
• Tighten the bleed valve, and install the rubber cap.

  Torque - Bleed Valves: 7.8 N·m (0.80 kgf·m, 69 in·lb)

• Check the fluid level (see Brake Fluid Level Inspection in the Periodic Maintenance chapter).
• After bleeding is done, check the brake for good braking power, no brake drag, and no fluid leakage.