2005 YAMAHA YZ250F brake

5 - 14
CHASFRONT BRAKE AND REAR BRAKE
EC5A3000
REMOVAL POINTS
Brake fluid
1. Remove:
[Front]
Brake master cylinder cap 1
[Rear]
Brake master cylinder cap 1
Protector
NOTE:
Do not remove the diaphragm.
È
Front
ÉRear
2. Connect the transparent hose 2 to the
bleed screw 1 and place a suitable con-
tainer under its end.
È
Front
ÉRear
È
É
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.
ÈÉ
Brake caliper piston
1. Remove:
Brake 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.
È
Front
ÉRear
Caliper piston removal steps:
Insert a piece of rag into the brake caliper
to lock one brake caliper.
Carefully force the piston out of the brake
caliper cylinder with compressed air.
È
É

5 - 15
CHASFRONT BRAKE AND REAR BRAKE
Brake caliper 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.
È
Front
ÉRear
È
É
EC5A4000
INSPECTION
Brake master cylinder
1. Inspect:
Brake master cylinder inner surface a
Wear/scratches → Replace master cylin-
der assembly.
Stains → Clean.
WARNING
Use only new brake fluid.
È
Front
ÉRear
2. Inspect:
Diaphragm 1
Crack/damage → Replace.
È
Front
ÉRear
ÈÉ
ÈÉ
3. Inspect: (front brake only)
Reservoir float 1
Damage → Replace.

5 - 16
CHAS
4. Inspect:
Brake master cylinder piston 1
Brake master cylinder cup 2
Wear/damage/score marks → Replace
brake master cylinder kit.
È
Front
ÉRear
ÈÉ
Brake caliper
1. Inspect:
Brake caliper cylinder inner surface a
Wear/score marks → Replace brake cali-
per assembly.
È
Front
ÉRear
ÈÉ
2. Inspect:
Brake caliper piston 1
Wear/score marks → Replace brake cali-
per 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
Brake caliper piston
1. Clean:
Brake caliper
Piston seal
Dust seal
Brake 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 brake caliper correctly.
È
Front
ÉRear
È
É
3. Install:
Brake caliper piston 1
NOTE:
Apply the brake fluid on the piston wall.
CAUTION:
Install the piston with its shallow
depressed side a facing the brake cali-
per.
Never force to insert.
È
Front
ÉRear
Front brake caliper
1. Install:
Pad support 1
Brake pad 2
Pad pin 3
NOTE:
Install the brake pads with their projections
a into the brake caliper recesses b.
Temporarily tighten the pad pin at this point.
È
É
FRONT BRAKE AND REAR BRAKE

5 - 18
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Brake caliper 1
Bolt (brake 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)
Rear brake caliper
1. Install:
Pad support 1
Brake pad 2
Pad pin 3
NOTE:
Install the brake pads with their projections
a into the brake caliper recesses b.
Temporarily tighten the pad pin at this point.
2. Install:
Brake disc cover 1
Bolt (brake disc cover) 2
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)

5 - 19
CHASFRONT BRAKE AND REAR BRAKE
3. Install:
Brake caliper 1
Rear wheel 2
Refer to “FRONT WHEEL AND REAR
WHEEL” section.
4. Tighten:
Pad pin 3
5. Install:
Pad pin plug 4
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)
Brake master cylinder kit
1. Clean:
Brake master cylinder
Brake master cylinder kit
Clean them with brake fluid.
2. Install:
Brake master cylinder cup (primary) 1
Brake master cylinder cup (secondary) 2
To brake master cylinder piston 3.
NOTE:
Apply the brake fluid on the brake master cylin-
der cup.
WARNING
After installing, cylinder cup should be
installed as shown direction. Wrong instal-
lation cause improper brake performance.
È
Front
ÉRear
ÈÉ
ÈÉ
3. Install:
Spring 1
To brake master cylinder piston 2.
NOTE:
Install the spring at the smaller dia. side.
È
Front
ÉRear
ÈÉ

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CHASFRONT BRAKE AND REAR BRAKE
4. Install:
[Front]
Brake master cylinder kit 1
Washer 2
Circlip 3
Brake master cylinder boot 4
To brake master cylinder 5.
[Rear]
Brake master cylinder kit 1
Push rod 2
Circlip 3
Brake master cylinder boot 4
To brake master cylinder 5.
NOTE:
Apply the brake fluid on the brake master cyl-
inder kit.
Apply the lithium soap base grease on the tip
of the push rod.
When installing the circlip, use a long nose
circlip pliers.
È
Front
ÉRear
È
É
Front brake master cylinder
1. Install:
Brake master cylinder 1
Brake master cylinder bracket 2
Bolt (brake 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
brake 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 brake master cylinder piston.
Rear brake 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 brake
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)
T R..30 Nm (3.0 m · kg, 22 ft · lb)
2. Install:
Brake master cylinder 1
Bolt (brake 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..11 Nm (1.1 m · kg, 8.0 ft · lb)
T R..26 Nm (2.6 m · kg, 19 ft · lb)