3. Replace a bleed valve with damaged threads or
with a rounded hex head. A damaged valve is diffi-
cult to remove and it cannot be properly tightened.
NOTE
The catch hose (
Figure 2
) is the hose
installed between the bleed valve and
the catch bottle.
4. Use a clear catch hose so the fluid can be visu-
ally inspected as it leaves the bleed valve. Air bub-
bles in the catch hose indicate that air may be
trapped in the brake system.
5. Open the bleed valve just enough to allow fluid
to pass through the valve and into the catch bottle. If
a bleed valve is too loose, air can be drawn into the
system through the valve threads.
6. If air may be entering through the valve threads,
apply silicone brake grease around the valve where
it emerges from the caliper. The grease should seal
the valve and prevent the entry of air. Wipe away
the grease once the brakes have been bled. For a
more permanent solution, remove the bleed valve
and apply Teflon tape to the valve threads. Reinstall
the valve and torque it to 6 N•m (53 in.-lb.). Make
sure the Teflon tape does not cover the passage in
the bleed valve.
7. If the system is difficult to bleed, tap the banjo
bolt on the master cylinder a few times. This should
dislodge air bubbles that may have become trapped
at the hose connection. Also tap the banjo bolts at
the brake hose union (beneath the lower fork
bridge), at the calipers and any other hose connec-
tions in the brake line.
Manual Bleeding
1. Check all banjo bolts in the system. They must
be tight.
2. Remove the dust cap from the bleed valve on the
caliper assembly.
3. Connect a length of clear tubing to the bleed
valve (
Figure 2
, typical). Place the other end of the
tube into a clean container. Fill the container with
enough fresh brake fluid to keep the end sub-
merged. The tube should be long enough that its
loop is higher than the bleed valve to prevent air
from being drawn into the caliper during bleeding.
NOTE
When bleeding the front brakes, turn
the handlebars to level the front mas
ter cylinder.
4. Clean all debris from the top of the master cylin-
der reservoir. Remove the top cover, diaphragm
plate and the diaphragm from the reservoir.
5. Add brake fluid to the reservoir until the fluid
level reaches the reservoir upper limit. Loosely in-
stall the diaphragm and the cover. Leave them in
place during this procedure to keep dirt out of the
system and so brake fluid cannot spurt out of the
reservoir.
6. Pump the brake lever or brake pedal a few times,
then release it.
7. Apply the brake lever or pedal until it stops and
hold it in this position.
8. Open the bleed valve with a wrench (
Figure 2
,
typical). Let the brake lever or pedal move to the
limit of its travel, then close the bleed valve. Do not
release the brake lever or pedal while the bleed
valve is open.
NOTE
As break fluid enters the system, the
level in the reservoir drops. Add brake
fluid as necessary to keep the fluid
level 10 mm (3/8 in.) below the reser
350
CHAPTER THIRTEEN
2
Catch hose
Box end wrench
Catch bottle
