brake fluid YAMAHA YZ450F 2004 User Guide

5 - 14
CHASFRONT BRAKE AND REAR BRAKE
EC5A3000
REMOVAL POINTS
Brake fluid
1. Remove:
[Front]
Master cylinder cap 1
[Rear]
Master cylinder cap 1
Protector
NOTE:
Do not remove the diaphragm.
ÅFront
ıRear
2. Connect the transparent hose 2 to the
bleed screw 1 and place a suitable con-
tainer under its end.
ÅFront
ıRear
Å
ı
3. Loosen the bleed screw and drain the
brake fluid while pulling the lever in or
pushing down on the pedal.
CAUTION:
Do not reuse the drained brake fluid.
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled
fluid immediately.
EC533301
Caliper piston
1. Remove:
Caliper piston
Use compressed air and proceed care-
fully.
WARNING
Cover piston with rag and use extreme
caution when expelling piston from cylin-
der.
Never attempt to pry out piston.
ÅFront
ıRear
Caliper piston removal steps:
Insert a piece of rag into the caliper to lock
one caliper.
Carefully force the piston out of the caliper
cylinder with compressed air.
ı
Å
Å
ı

5 - 15
CHASFRONT BRAKE AND REAR BRAKE
EC533402
Piston seal kit
1. Remove:
Dust seal 1
Piston seal 2
NOTE:
Remove the piston seals and dust seals by
pushing them with a finger.
CAUTION:
Never attempt to pry out piston seals and
dust seals.
WARNING
Replace the piston seals and dust seals
whenever a caliper is disassembled.
ÅFront
ıRear
Å
ı
EC5A4000
INSPECTION
EC534112
Master cylinder
1. Inspect:
Master cylinder inner surface a
Wear/scratches → Replace master cyl-
inder assembly.
Stains → Clean.
WARNING
Use only new brake fluid.
ÅFront
ıRear
2. Inspect:
Diaphragm 1
Crack/damage → Replace.
ÅFront
ıRear
ı
Å
ı
Å
3. Inspect: (front brake only)
Reservoir float 1
Damage → Replace.

5 - 16
CHAS
4. Inspect:
Master cylinder piston 1
Master cylinder cup 2
Wear/damage/score marks → Replace
master cylinder kit.
ÅFront
ıRear
Åı
EC534214
Caliper
1. Inspect:
Caliper cylinder inner surface a
Wear/score marks → Replace caliper
assembly.
ÅFront
ıRear
ı Å
2. Inspect:
Caliper piston 1
Wear/score marks → Replace caliper
piston assembly.
WARNING
Replace the piston seals and dust seals 2
whenever a caliper is disassembled.
EC534301
Brake hose
1. Inspect:
Brake hose 1
Crack/damage → Replace.
EC5A5000
ASSEMBLY AND INSTALLATION
WARNING
All internal parts should be cleaned in
new brake fluid only.
Internal parts should be lubricated with
brake fluid when installed.
Replace the piston seals and dust seals
whenever a caliper is disassembled.
FRONT BRAKE AND REAR BRAKE

5 - 17
CHAS
EC5A5800
Caliper piston
1. Clean:
Caliper
Piston seal
Dust seal
Caliper piston
Clean them with brake fluid.
2. Install:
Piston seal 1
Dust seal 2
WARNING
Always use new piston seals and dust
seals.
NOTE:
Fit the piston seals and dust seals onto the slot
on caliper correctly.
ÅFront
ıRear
3. Install:
Caliper piston 1
NOTE:
Apply the brake fluid on the piston wall.
CAUTION:
Install the piston with its shallow
depressed side a facing the caliper.
Never force to insert.
ÅFront
ıRear
EC5A5700
Front caliper
1. Install:
Pad support 1
Brake pad 2
Pad pin 3
NOTE:
Install the brake pads with their projections
a into the caliper recesses b.
Temporarily tighten the pad pin at this point.
Å
New
Newı
Å
ı
FRONT BRAKE AND REAR BRAKE

5 - 19
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Disc cover 1
Bolt (disc cover) 2
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
3. Install:
Caliper 1
Rear wheel 2
Refer to “FRONT WHEEL AND REAR
WHEEL” section.
4. Tighten:
Pad pin 3
5. Install:
Pad pin plug 4
Master cylinder kit
1. Clean:
Master cylinder
Master cylinder kit
Clean them with brake fluid.
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)
2. Install:
Master cylinder cup (primary) 1
Master cylinder cup (secondary) 2
To master cylinder piston 3.
NOTE:
Apply the brake fluid on the master cylinder
cup.
WARNING
After installing, cylinder cup should be
installed as shown direction. Wrong instal-
lation cause improper brake performance.
ÅFront
ıRear
Åı
Åı

5 - 20
CHASFRONT BRAKE AND REAR BRAKE
3. Install:
Spring 1
To master cylinder piston 2.
NOTE:
Install the spring at the smaller dia. side.
ÅFront
ıRear
Åı
4. Install:
[Front]
Master cylinder kit 1
Plain washer 2
Circlip 3
Master cylinder boot 4
To master cylinder 5.
[Rear]
Master cylinder kit 1
Push rod 2
Circlip 3
Master cylinder boot 4
To master cylinder 5.
NOTE:
Apply the brake fluid on the master cylinder
kit.
Apply the lithium soap base grease on the tip
of the push rod.
When installing the circlip, use a long nose
circlip pliers.
ÅFront
ıRear
EC5A5310
Front master cylinder
1. Install:
Master cylinder 1
Master cylinder bracket 2
Bolt (master cylinder bracket) 3
NOTE:
Install the bracket so that the arrow mark a
face upward.
First tighten the bolts on the upper side of the
master cylinder bracket, and then tighten the
bolts on the lower side.
Å
ı
T R..9 Nm (0.9 m · kg, 6.5 ft · lb)

5 - 24
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Brake hose holder 1
Screw (brake hose holder) 2
CAUTION:
After installing the brake hose holders,
make sure the brake hose does not contact
the spring (rear shock absorber). If it does,
correct its twist.
T R..1 Nm (0.1 m · kg, 0.7 ft · lb)
Brake fluid
1. Fill:
Brake fluid
Until the fluid level reaches “LOWER”
level line a.
WARNING
Use only the designated quality brake
fluid:
otherwise, the rubber seals may deterio-
rate, causing leakage and poor brake per-
formance.
Refill with the same type of brake fluid;
mixing fluids may result in a harmful chem-
ical reaction and lead to poor performance.
Be careful that water does not enter the
master cylinder when refilling. Water will
significantly lower the boiling point of the
fluid and may result in vapor lock.
CAUTION:
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
ÅFront
ıRear
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
Master cylinder cap 1
Screw (master cylinder cap) 2
[Rear]
Diaphragm
Master cylinder cap 1
Bolt (master cylinder cap) 2
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.
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)