Kawasaki J300 - Service manual > Brake Fluid
Brake Fluid Level Inspection
- Refer to the Brake Fluid Level Inspection in the Periodic Maintenance chapter.
Brake Fluid Change
- Refer to the Brake Fluid Change in the Periodic Maintenance chapter.
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.
WARNING Air in the brake lines diminish braking performance and can cause an accident resulting in injury or death. If the brake lever has a soft or "spongy" feeling mushy when it is applied, there might be air in the brake lines or the brake may be defective. Do not operate the vehicle and service the brake system immediately.
- The procedure to bleed the front brake line is as follows.
Bleeding the rear brake line is the same as for the front brake.
Brake Reservoir Cap [B]
- 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.
- 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.
- Pump the brake lever until it becomes hard, and apply the brake and hold it [A].
- Quickly open and close [B] the bleed valve while holding the brake applied.
- Release the brake [C].
NOTICE After pumping the brake lever several times, releasing it without opening and closing of the bleed valve may cause brake fluid to be blown back from the master cylinder reservoir. Brake fluid spilt on painted surfaces and plastic parts will quickly damage them. Be sure to open and close the bleed valve.
- 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.
- Remove the clear plastic hose.
Brake Reservoir Cap
Torque - Brake Reservoir Cap Screws: 1.6 N*m (0.16 kgf*m, 14 in*lb)
- Tighten the bleed valve, and install the rubber cap.
Torque - Bleed Valve: 5.4 N*m (0.55 kgf*m, 48 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.
WARNING When working with the disc brake, observe the precautions listed below.
- Never reuse old brake fluid.
- Do not use fluid from a container that has been left unsealed or that has been open for a long time.
- Do not mix two types and brands of fluid for use in the brake.
This lowers the brake fluid boiling point and could cause the brake to be
It may also cause the rubber brake parts to deteriorate.
- Don't leave the reservoir cap off for any length of time to avoid moisture contamination of the fluid.
- Don't change the fluid in the rain or when a strong wind is blowing.
- Except for the disc pads and disc, use only disc brake fluid, isopropyl alcohol, or ethyl alcohol for cleaning of the brake parts. Do not use any other fluid for cleaning these parts. Gasoline, engine oil, or any other petroleum distillate will cause deterioration of the rubber parts. Oil spilled on any part will be difficult to wash off completely and will eventually deteriorate the rubber used in the disc brake.
- When handling the disc pads or disc, be careful that no disc
brake fluid or any oil gets on them.
Clean off any fluid or oil that inadvertently gets on the pads or disc with a high flash-point solvent.
Do not use one which will leave an oily residue.
Replace the pads with new ones if they cannot be cleaned satisfactorily.
- Brake fluid quickly ruins painted surfaces; any spilled fluid should be completely wiped up immediately.
- If any of the brake line fittings or the bleed valve is opened at any time, the AIR MUST BE BLED FROM THE BRAKE LINE.
Brake Hose Removal/Installation
- Refer to the Brake Hose and Pipe Replacement in the Periodic Maintenance chapter.
Brake Hose Inspection
- Refer to the Brake Hose and Pipe Damage and Installation Condition Inspection in the Periodic Maintenance chapter.
Brake Disc Removal Remove the wheels (see Front/Rear Wheel Removal in the Wheels/Tires chapter). Remove the brake disc mounting bolts [A], and take off the disc [B]. Remove the wheel rotation sensor (speed sensor) rotor [C]. For rear wheel, the rear brake disc has the wheel rotation sensor only on ABS model.