2004 YAMAHA YZ450F brake

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 - 18
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Copper washer 1
Union bolt 2
WARNING
Always use new copper washers.
CAUTION:
Install the brake hose so that its pipe por-
tion a directs as shown and lightly
touches the projection b on the caliper.
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)
3. Install:
Brake hose holder 1
Caliper 2
Bolt (caliper) 3
NOTE:
Fit the brake hose holder cut a over the pro-
jection b on the front fork and clamp the brake
hose.
4. Tighten:
Pad pin 4
5. Install:
Pad pin plug 5
EC5A5100
Rear 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.
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)

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 - 21
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Brake lever 1
Bolt (brake lever) 2
Nut (brake lever) 3
NOTE:
Apply the lithium soap base grease on the
brake lever sliding surface, bolt and contacting
surface of the master cylinder piston.
Rear master cylinder
1. Install:
Copper washer 1
Brake hose 2
Union bolt 3
WARNING
Always use new copper washers.
CAUTION:
Install the brake hose so that its pipe por-
tion a directs as shown and lightly
touches the projection b on the master
cylinder.
T R..6 Nm (0.6 m · kg, 4.3 ft · lb)
T R..6 Nm (0.6 m · kg, 4.3 ft · lb)
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)
2. Install:
Master cylinder 1
Bolt (master cylinder) 2
3. Install:
Spring 1
Brake pedal 2
O-ring 3
Bolt (brake pedal) 4
Clip 5
NOTE:
Apply the lithium soap base grease on the
bolt, O-ring and brake pedal bracket.
Install the clip with its stopper portion a fac-
ing inward.
T R..11 Nm (1.1 m · kg, 8.0 ft · lb)
New
T R..26 Nm (2.6 m · kg, 19 ft · lb)