Bleeding The Hydraulic Brake System - Yamaha MBK MW125 2014 Service Manual

A
a
B
A. Front brake
B. Rear brake
EWA13540
WARNING
• Use only the designated brake fluid. Other
brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor
brake performance.
• Refill with the same type of brake fluid that
is already in the system. Mixing brake fluids
may result in a harmful chemical reaction,
leading to poor brake performance.
• When refilling, be careful that water does
not enter the brake master cylinder reser-
voir. Water will significantly lower the boil-
ing point of the brake fluid and could cause
vapor lock.
ECA13540
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean up
any spilt brake fluid immediately.
EAS30637
BLEEDING THE HYDRAULIC BRAKE
SYSTEM
EWA17980
WARNING
Bleed the hydraulic brake system whenever:
• the system is disassembled.
• a brake hose is loosened, disconnected or
replaced.
• the brake fluid level is very low.
a
3-12
PERIODIC MAINTENANCE
• the brake operation is faulty.
TIP
• Be careful not to spill any brake fluid or allow
the brake master cylinder reservoir to overflow.
• When bleeding the hydraulic brake system,
make sure there is always enough brake fluid
before applying the brake. Ignoring this pre-
caution could allow air to enter the hydraulic
brake system, considerably lengthening the
bleeding procedure.
• If bleeding is difficult, it may be necessary to let
the brake fluid settle for a few hours. Repeat
the bleeding procedure when the tiny bubbles
in the hose have disappeared.
1. Bleed:
• Front hydraulic brake system
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a. Fill the brake master cylinder reservoir to the
proper level with the specified brake fluid.
b. Install the diaphragm (brake master cylinder
reservoir).
c. Connect a clear plastic hose "1" tightly to the
bleed screw "2".
1
2
d. Place the other end of the hose into a con-
tainer.
e. Slowly apply the brake several times.
f. Fully pull the brake lever and hold it in posi-
tion.
g. Loosen the bleed screw.
TIP
Loosening the bleed screw will release the pres-
sure and cause the brake lever to contact the
throttle grip.
h. Tighten the bleed screw, and then release
the brake lever.
i. Repeat steps (e) to (h) until all of the air bub-
bles have disappeared from the brake fluid in
the plastic hose.
j. Tighten the bleed screw to specification.
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