Bleeding the Brake Line
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.
Be sure to bleed the air from the brake line when-
ever brake lever or pedal action feels soft or
spongy after the brake fluid is changed, or when-
ever a brake line fitting has been loosened for any
The procedure to bleed the front brake line is as follows.
Bleeding the rear brake line is the same as for the front
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
Install the reservoir cap.
Remove the rubber cap from the bleed valve on the
Attach a clear plastic hose 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 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].
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 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 reser-
voir for more complete bleeding.
Front Brake: Repeat the above steps for the other
Remove the clear plastic hose.
PERIODIC MAINTENANCE 2-35