Yamaha Wr250r 2008 Manual

 
FRONT BRAKE 
4-21 
EAS22520 
ASSEMBLING THE FRONT BRAKE MASTER 
CYLINDER
WARNING
 
EWA13520  
 
Before installation, all internal brake com-
ponents should be cleaned and lubricated
with clean or new brake fluid. 
 
Never use solvents on internal brake com- 
ponents. 
1. Install: 
 
Master cylinder cup 
 
Master cylinder piston
2. Install: 
 
Circlip “1” 
 
Dust boot “2” 
EAS22530 
INSTALLING THE FRONT BRAKE MASTER 
CYLINDER 
1. Install: 
 
Brake master cylinder “1”
NOTE:
 
 
Install the brake...

 
FRONT BRAKE 
4-22 
brake performance. 
 
Refill with the same type of brake fluid that
is already in the system. Mixing brake flu-
ids may result in a harmful chemical reac-
tion, leading to poor brake performance. 
 
When refilling, be careful that water does
not enter the brake master cylinder reser-
voir. Water will significantly lower the boil-
ing point of the brake fluid and could cause 
vapor lock.
CAUTION:
 
 ECA13540 
Brake fluid may damage painted surfaces
and plastic parts. Therefore,...

 
REAR BRAKE 
4-23 
EAS22550 
REAR BRAKE 
Removing the rear brake pads
Order Job/Parts to remove Q’ty Remarks  
Rear wheel Refer to“REAR WHEEL” on page 4-7.
1 Protector 1
2 Pin plug 1
3 Brake pad support bolt 1
4 Rear brake pad 2
5 Pad shim 2
6 Insulator 2
7 Rear brake pad spring 1
8 Rear brake caliper assembly 1
For installation, reverse the removal proce-
dure.
1 2 3
4 5
5 6
6 7 8
T R..7 Nm (0.7 m • kg, 5.1 ft • Ib) 
T R..17 Nm (1.7 m • kg, 12 ft • Ib) 
T R..2.5 Nm (0.25 m • kg, 1.8 ft • Ib)  

 
REAR BRAKE 
4-24 
Removing the rear brake master cylinder
Order Job/Parts to remove Q’ty Remarks  
Brake fluidDrain.
Refer to “BLEEDING THE HYDRAULIC 
BRAKE SYSTEM” on page 1-25.
1 Union bolt 1
2 Copper washer 2
3 Brake hose 1
4 Split pin 1
5 Plain washer 1
6 Pin 1
7 Brake master cylinder reservoir cap 1
8 Brake master cylinder reservoir diaphragm plate 1
9 Brake master cylinder reservoir diaphragm 1
10 Rear brake master cylinder 1
For installation, reverse the removal proce-
dure.
1
2
3
4 7
5 8
6 9
10...

 
REAR BRAKE 
4-25 
Disassembling the rear brake master cylinder
Order Job/Parts to remove Q’ty Remarks  
1 Master cylinder kit 1
For assembly, reverse the disassembly pro-
cedure.
S1
T R..12 Nm (1.2 m • kg, 8.7 ft • Ib)  

 
REAR BRAKE 
4-26 
Removing the rear brake calipers
Order Job/Parts to remove Q’ty Remarks  
Brake fluidDrain.
Refer to“BLEEDING THE HYDRAULIC 
BRAKE SYSTEM” on page 1-25.
Protector Refer to“REAR BRAKE” on page 4-23.
1 Union bolt 1
2 Copper washer 2
3 Rear brake hose 1
4 Pin plug 1
5 Brake caliper support bolt 1
6 Rear brake pad assemblyl 2
7 Rear brake caliper bracket 1
8 Brake pad spring 2
9 Rear brake caliper assembly 1
For installation, reverse the removal proce-
dure.
1
2
3
45
6 78
89
S
T R..30 Nm...

 
REAR BRAKE 
4-27 
Disassembling the rear brake calipers
Order Job/Parts to remove Q’ty Remarks  
1 Brake caliper piston 1
2 Brake caliper dust seal 1
3 Brake caliper piston seal 1
4 Bleed screw 1
For assembly, reverse the disassembly pro-
cedure.
1
2
3
4
S
BF
T R..6 Nm (0.6 m • kg, 4.3 ft • Ib)  

 
REAR BRAKE 
4-28 
EAS22560 
INTRODUCTION
WARNING
 
EWA14100  
Disc brake components rarely require disas-
sembly. Therefore, always follow these pre-
ventive measures: 
 
Never disassemble brake components un-
less absolutely necessary. 
 
If any connection on the hydraulic brake
system is disconnected, the entire brake
system must be disassembled, drained,
cleaned, properly filled, and bled after reas-
sembly. 
 
Never use solvents on internal brake com-
ponents. 
 
Use only clean or new brake...

 
REAR BRAKE 
4-29 
and a brake pad spring as a set.

 
a. Connect a clear plastic hose “1” tightly to the
bleed screw “2”. Put the other end of the hose
into an open container.
b. Loosen the bleed screw and push the brake
caliper pistons into the brake caliper with your
finger.
c. Tighten the bleed screw.
d. Install a new brake pad shim onto each new
brake pad.
e. Install new brake pads and a new brake pad
spring.
NOTE:
 
The longer tangs “b” of the brake pad spring 
must...

 
REAR BRAKE 
4-30
WARNING
 
EWA13550  
 
Cover the brake caliper piston with a rag.
Be careful not to get injured when the pis-
ton is expelled from the brake caliper. 
 
Never try to pry out the brake caliper pis- 
ton. 
b. Remove the brake caliper dust seals brake
caliper piston seals.

 
EAS22640 
CHECKING THE REAR BRAKE CALIPER 
1. Check: 
 
Brake caliper pistons “1”
Rust/scratches/wear  
→ 
 Replace the brake
caliper pistons. 
 
Brake caliper cylinders “2”...