2004 YAMAHA YZ250F air bleeding

3 - 24
INSP
ADJ

CHASSIS/BRAKE SYSTEM AIR BLEEDING
EC360000
CHASSIS
EC361012
BRAKE SYSTEM AIR BLEEDING
WARNING

Bleed the brake system if:

The system has been disassembled.

A brake hose has been loosened or
removed.

The brake fluid is very low.

The brake operation is faulty.
A dangerous loss of braking performance
may occur if the brake system is not prop-
erly bled.
1. Remove:

Brake master cylinder cap

Diaphragm

Reservoir float (front brake)

Protector (rear brake)
2. Bleed:

Brake fluid
Å
Front
ı
Rear
Air bleeding steps:
a. Add proper brake fluid to the reservoir.
b. Install the diaphragm. Be careful not to
spill any fluid or allow the reservoir to
overflow.
c. Connect the clear plastic tube
2
tightly
to the caliper bleed screw
1
.
d. Place the other end of the tube into a
container.
e. Slowly apply the brake lever or pedal
several times.
f. Pull the lever in or push down on the
pedal. Hold the lever or pedal in position.
g. Loosen the bleed screw and allow the
lever or pedal to travel towards its limit.
h. Tighten the bleed screw when the lever
or pedal limit has been reached; then
release the lever or pedal.
T R..

Bleed screw:
6 Nm (0.6 m • kg, 4.3 ft • lb)
i. Repeat steps (e) to (h) until of the air
bubbles have been removed from the
system.
Å
ı

3 - 28
INSP
ADJ
REAR BRAKE PAD INSPECTION AND REPLACEMENT
3. Inspect:
Brake fluid level
Refer to “BRAKE FLUID LEVEL
INSPECTION” section.
Install the pad pin plug B.
T R..
Pad pin plug:
3 Nm (0.3 m • kg, 2.2 ft • lb)
4. Check:
Brake lever operation
A softy or spongy feeling → Bleed
brake system.
Refer to “BRAKE SYSTEM AIR
BLEEDING” section.
REAR BRAKE PAD INSPECTION AND
REPLACEMENT
1. Inspect:
Brake pad thickness a
Out of specification → Replace as a
set.
2. Replace:
Brake pad
Brake pad thickness:
6.4 mm (0.25 in)
: 1.0 mm (0.04 in)
Brake pad replacement steps:
Remove the protector 1 and pad pin plug
2.
Loosen the pad pin 3.
Remove the rear wheel 4 and brake cali-
per 5.
Refer to “FRONT WHEEL AND REAR
WHEEL” section in the CHAPTER 5.

3 - 30
INSP
ADJREAR BRAKE PAD INSULATOR INSPECTION/
BRAKE FLUID LEVEL INSPECTION
3. Inspect:
Brake fluid level
Refer to “BRAKE FLUID LEVEL
INSPECTION” section.
4. Check:
Brake pedal operation
A softy or spongy feeling → Bleed
brake system.
Refer to “BRAKE SYSTEM AIR
BLEEDING” section.
EC36b000
REAR BRAKE PAD INSULATOR
INSPECTION
1. Remove:
Brake pad
Refer to “REAR BRAKE PAD INSPEC-
TION AND REPLACEMENT” section.
2. Inspect:
Rear brake pad insulator 1
Damage → Replace.
BRAKE FLUID LEVEL INSPECTION
1. Place the brake master cylinder so that
its top is in a horizontal position.
2. Inspect:
Brake fluid level
Fluid at lower level → Fill up.
aLower level
ÅFront
ıRear
WARNING
Use only designated quality brake fluid to
avoid poor brake performance.
Refill with same type and brand of brake
fluid; mixing fluids could result in poor
brake performance.
Be sure that water or other contaminants
do not enter master cylinder when refill-
ing.
Clean up spilled fluid immediately to
avoid erosion of painted surfaces or plas-
tic parts.
Recommended brake fluid:
DOT #4
Å
ı

5 - 25
CHASFRONT BRAKE AND REAR BRAKE
2. Air bleed:
Brake system
Refer to “BRAKE SYSTEM AIR
BLEEDING” section in the CHAPTER
3.
3. Inspect:
Brake fluid level
Fluid at lower level → Fill up.
Refer to “BRAKE FLUID LEVEL
INSPECTION” section in the CHAP-
TER 3.
4. Install:
[Front]
Reservoir float
Diaphragm
Brake master cylinder cap 1
Screw (brake master cylinder cap) 2
[Rear]
Diaphragm
Brake master cylinder cap 1
Bolt (brake master cylinder cap) 2
CAUTION:
After installation, while pulling the brake
lever in or pushing down on the brake
pedal, check whether there is any brake
fluid leaking where the union bolts are
installed respectively at the brake master
cylinder and brake caliper.
ÅFront
ıRear
5. Install: (rear brake only)
Protector 1
Bolt (protector) 2
Å
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
ı
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)