2003 YAMAHA YZ250F brake fluid

5 - 10
CHASFRONT BRAKE AND REAR BRAKE
EC5A0000
FRONT BRAKE AND REAR BRAKE
EC5A8000
FRONT BRAKE
Extent of removal:1 Brake hose removal2 Brake caliper removal
3 Brake master cylinder removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalFRONT BRAKE REMOVAL
Hold the machine by placing the
suitable stand under the engine.
Drain the brake fluid.
WARNING
Support the machine securely so there is nodanger of it falling over.
Refer to “REMOVAL POINTS”.
1 Brake hose cover 1
2 Brake hose holder 1
3 Bolt (brake hose holder) 2 Only loosening.
4 Union bolt 2
5 Brake hose 1
6 Pad pin plug 1 Remove when loosening the pad pin.
7 Pad pin 1 Loosen when disassembling the caliper.
8 Brake caliper 1
9 Brake lever 1
10 Brake master cylinder bracket 1
11 Brake master cylinder 1
2
3
1
3
2

5 - 11
CHAS
EC5A8100
REAR BRAKE
Extent of removal:1 Brake master cylinder removal2 Brake hose removal
3 Brake caliper removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalREAR BRAKE REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is nodanger of it falling over.
Rear wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Drain the brake fluid. Refer to “REMOVAL POINTS”.
1 Brake pedal 1
2 Master cylinder 1
3 Brake hose holder 2
4 Union bolt 2
5 Brake hose 1
6 Pad pin plug 1 Remove when loosening the pad pin.
7 Pad pin 1 Loosen when disassembling the caliper.
8 Caliper 1
3
1
321
FRONT BRAKE AND REAR 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.
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.
ACHTUNG:CAUTION:
Do not reuse the drained brake fluid.
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled
fluid immediately.
ı
Å
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.
ÅFront
ıRear
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.
Å
ı

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.
ACHTUNG: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
Brake master cylinder
1. Inspect:
Brake 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:
Brake master cylinder piston 1
Brake master cylinder cup 2
Wear/damage/score marks → Replace
brake master cylinder kit.
ÅFront
ıRear
Åı

5 - 16
CHAS
Brake caliper
1. Inspect:
Brake caliper cylinder inner surface a
Wear/score marks → Replace brake
caliper assembly.
ÅFront
ıRear
ı Å
2. Inspect:
Brake caliper piston 1
Wear/score marks → Replace brake
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.
Brake caliper piston
1. Clean:
Brake caliper
Piston seal
Dust seal
Brake caliper piston
Clean them with brake fluid.
FRONT BRAKE AND REAR BRAKE

5 - 17
CHAS
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.
ÅFront
ıRear
Å
ı
3. Install:
Brake caliper piston 1
NOTE:
Apply the brake fluid on the piston wall.
ACHTUNG:CAUTION:
Install the piston with its shallow
depressed side a facing the brake cali-
per.
Never force to insert.
ÅFront
ıRear
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.
Å
ı
FRONT BRAKE AND REAR BRAKE

5 - 19
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Brake disc cover 1
Bolt (brake disc cover) 2
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
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
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 cyl-
inder cup.
WARNING
After installing, cylinder cup should be
installed as shown direction. Wrong instal-
lation cause improper brake performance.
ÅFront
ıRear
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)Åı
Åı

5 - 20
CHASFRONT BRAKE AND REAR BRAKE
3. Install:
Spring 1
To brake master cylinder piston 2.
NOTE:
Install the spring at the smaller dia. side.
ÅFront
ıRear
Åı
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
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
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.
Å
ı
T R..9 Nm (0.9 m · kg, 6.5 ft · lb)