brake YAMAHA YZ450F 2007 Service Manual

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.
ÈFront
ÉRear
È
É
EC5A4000
INSPECTION
EC534112
Master cylinder
1. Inspect:
Master cylinder inner surface
a
Wear/scratches → Replace master cylin-
der assembly.
Stains → Clean.
WARNING
Use only new brake fluid.
ÈFront
ÉRear
2. Inspect:
Diaphragm 1
Crack/damage → Replace.
ÈFront
ÉRear
ÈÉ
ÈÉ
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.
ÈFront
ÉRear
ÈÉ
EC534214
Caliper
1. Inspect:
Caliper cylinder inner surface
a
Wear/score marks → Replace caliper
assembly.
ÈFront
ÉRear
ÈÉ
2. Inspect:
Caliper piston 1
Wear/score marks → Replace caliper pis-
ton 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.
ÈFront
ÉRear
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.
ÈFront
ÉRear
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.
È
New
New
É
È
É
FRONT BRAKE AND REAR BRAKE

5 - 18
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Caliper 1
Bolt (caliper) 2
3. Tighten:
Pad pin 3
4. Install:
Pad pin plug 4
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)
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.
2. Install:
Disc cover 1
Bolt (disc cover) 2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

5 - 19
CHASFRONT BRAKE AND REAR BRAKE
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.
ÈFront
ÉRear
ÈÉ
ÈÉ
3. Install:
Spring 1
To master cylinder piston 2.
NOTE:
Install the spring at the smaller dia. side.
ÈFront
ÉRear
ÈÉ

5 - 20
CHASFRONT BRAKE AND REAR BRAKE
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.
ÈFront
ÉRear
È
É
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.
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.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
New
T R..26 Nm (2.6 m · kg, 19 ft · lb)

5 - 22
CHASFRONT BRAKE AND REAR BRAKE
4. Install:
Pin 1
Plain washer 2
Cotter pin 3
NOTE:
After installing, check the brake pedal height.
Refer to “REAR BRAKE ADJUSTMENT” sec-
tion in the CHAPTER 3.
New
Front brake hose
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 caliper.
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)
2. Install:
Brake hose holder 1
Bolt (brake hose holder) 2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
3. Install:
Brake hose holder 1
Nut (brake hose holder) 2
NOTE:
Align the top a of the brake hose holder with
the paint b of the brake hose.
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)

5 - 23
CHASFRONT BRAKE AND REAR BRAKE
4. Pass the brake hose through the cable
guide 1.
5. 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.
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)
Rear brake hose
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 caliper.
New
T R..30 Nm (3.0 m · kg, 22 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.
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
chemical reaction and lead to poor perfor-
mance.
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.
ÈFront
ÉRear
Recommended brake fluid:
DOT #4
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
È
É