HYOSUNG TE 450 Service Manual page 33

2-17 PERIODIC MAINTENANCE
▣ ▣ AIR BLEEDING OF THE BRAKE FLUID
CIRCUIT
Air trapped in the brake fluid circuit acts like a cush-
ion to absorb a large proportion of the pressure
developed by the master cylinder and thus interferes
with the full braking performance of the brake caliper.
The presence of air is indicated by "sponginess"of
the brake lever/pedal and also by lack of braking
force. Considering the danger to which such trapped
air exposes the machine and rider, it is essential that,
after remounting the brake and restoring the brake
system to the normal condition, the brake fluid circuit
be purged of air in the following manner :
● Fill the front or rear brake master cylinder with the
specified brake fluid to the top of the inspection
window or the upper limit line.
Replace the master cylinder cap to prevent dirt
from entering.
● Attach a hose to the air bleeder valve, and insert
the free end of the hose into a receptacle.
● Squeeze and release the brake lever or the brake
pedal several times in rapid succession and
squeeze the lever or push down the pedal fully
without releasing it. Loosen the air bleeder valve
by turning it a quarter of a turn so that the brake
fluid runs into the receptacle, this will remove the
tension of the brake lever causing it to touch the
handlebar grip or the brake pedal reaching bottom
of the stroke. Then, close the air bleeder valve,
pump and squeeze the brake lever or push down
the pedal and open the valve. Repeat this process
until the fluid flowing into the receptacle no longer
contains air bubbles.
NOTE
While bleeding the brake system, replenish the
brake fluid in the master cylinder as necessary.
Make sure that there is always some fluid visible
in the master cylinder.
● Close the air bleeder valve, and disconnect the
hose. Fill the master cylinder with brake fluid to
the top of the inspection window or the upper limit
line.
Brake caliper air bleeder valve
: 9 ~ 14 N∙ ∙ m (0.9 ~ 1.4 kgf∙ ∙ m)
CAUTION
Handle brake fluid with care : the fluid reacts
chemically with paint, plastics, rubber materials,
etc.