2001 YAMAHA WR 400F air bleeding

3 - 26
INSP
ADJ
CHASSIS/BRAKE SYSTEM AIR BLEEDING
EC360000
CHASSIS
EC361012
BRAKE SYSTEM AIR BLEEDING
WARNING
Bleed the brake system if:
lThe system has been disassembled.
lA brake hose has been loosened or
removed.
lThe brake fluid is very low.
lThe brake operation is faulty.
A dangerous loss of braking performance
may occur if the brake system is not prop-
erly bleed.
1. Remove:
lMaster cylinder cap
lDiaphragm
lProtector (rear brake)
2. Bleed:
lBrake fluid
Front
õRear
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.

õ

3 - 30
INSP
ADJ
REAR BRAKE PAD INSPECTION AND REPLACEMENT
3. Inspect:
lBrake fluid level
Refer to “BRAKE FLUID LEVEL
INSPECTION” section.
lInstall the pad pin plug B.
T R..
Pad pin plug:
3 Nm (0.3 m • kg, 2.2 ft • lb)
4. Check:
lBrake lever operation
A softy or spongy feeling ® Bleed
brake system.
Refer to “BRAKE SYSTEM AIR
BLEEDING” section.
EC366060
REAR BRAKE PAD INSPECTION AND
REPLACEMENT
1. Inspect:
lBrake pad thickness a
Out of specification ® Replace as a
set.
2. Replace:
lBrake pad
Brake pad thickness a:
Standard
6.4 mm (0.25 in) 1.0 mm (0.04 in)
Brake pad replacement steps:
lRemove the protector 1 and pad pin plug
2.
lLoosen the pad pin 3.
lRemove the rear wheel 4 and caliper 5.
Refer to “FRONT WHEEL AND REAR
WHEEL” section in the CHAPTER 5.

3 - 32
INSP
ADJREAR BRAKE PAD INSULATOR INSPECTION/
BRAKE FLUID LEVEL INSPECTION
3. Inspect:
lBrake fluid level
Refer to “BRAKE FLUID LEVEL
INSPECTION” section.
4. Check:
lBrake 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:
lBrake pad
Refer to “REAR BRAKE PAD INSPEC-
TION AND REPLACEMENT” section.
2. Inspect:
lRear brake pad insulator 1
Damage ® Replace.
EC367001
BRAKE FLUID LEVEL INSPECTION
1. Place the master cylinder so that its top is
in a horizontal position.
2. Inspect:
lBrake fluid level
Fluid at lower level ® Fill up.
aLower level
Front
õRear
WARNING
lUse only designated quality brake fluid to
avoid poor brake performance.
lRefill with same type and brand of brake
fluid; mixing fluids could result in poor
brake performance.
lBe sure that water or other contaminants
do not enter master cylinder when refill-
ing.
lClean up spilled fluid immediately to
avoid erosion of painted surfaces or plas-
tic parts.
Recommended brake fluid:
DOT #4

õ

5 - 27
CHASFRONT BRAKE AND REAR BRAKE
2. Air bleed:
lBrake system
Refer to “BRAKE SYSTEM AIR
BLEEDING” section in the CHAPTER
3.
3. Inspect:
lBrake fluid level
Fluid at lower level ® Fill up.
Refer to “BRAKE FLUID LEVEL
INSPECTION” section in the CHAP-
TER 3.
4. Install:
[Front]
lDiaphragm
lMaster cylinder cap 1
lScrew (master cylinder cap) 2
[Rear]
lDiaphragm
lReservoir tank cap 1
lScrew (reservoir tank cap) 2
lMaster cylinder guard
CAUTION:
After installation, while pulling the lever in
or pushing down on the pedal, check
whether there is any brake fluid leaking
where the union bolts are installed respec-
tively at the master cylinder and caliper.
Front
õRear
5. Install: (rear brake only)
lProtector 1
lBolt (protector) 2

T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
õ
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)