Bleeding the Brake Line
The brake fluid has a very low compression coefficient so
that almost all the movement of the brake lever is transmit-
ted directly to the caliper for braking action. Air, however, is
easily compressed. When air enters the brake line, brake
lever movement will be partially used in compressing the
air. This will make the lever feel spongy, and it will be a loss
in braking power.
Be sure to bleed the air from the brake line when-
ever brake lever action feels soft or spongy, after
the brake fluid is changed, or whenever a brake line
fitting has been loosened for any reason.
Remove the reservoir cap, and fill the reservoir with fresh
brake fluid to the upper level line in the reservoir.
With the reservoir cap off, 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 reser-
Bleed the air completely from the master cylinder by this
The fluid level must be checked often during the bleed-
ing operation and replenished with fresh brake fluid as
necessary. If the fluid in the reservoir runs almost out
any time during bleeding operation, the bleeding opera-
tion 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 reser-
voir for easier bleeding.
Install the reservoir cap.
Remove the rubber cap from the bleed valve on the
Attach a clear plastic hose to the bleed valve on the
caliper, and run the other end of the hose into a con-
Bleed the air from the caliper as follows:
Repeat this operation until no more air can be seen com-
ing 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].
Detach the clear plastic hose from the bleed valve.
Tighten the bleed valve to the specified torque, and install
the rubber cap.
Torque - Caliper Bleed Valve: 7.8 N·m (0.80 kgf·m, 69 in·lb)
Check the fluid level.
After bleeding is done, check the brake for good braking
power, no brake drag, and no fluid leakage.