Removing The Rear Brake Master Cylinder; Checking The Rear Brake Master Cylinder - Yamaha YZ250F(E) Owner's Service Manual

EWA13090
WARNING
• Use only the designated brake fluid. Other
brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor
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 pouring the brake fluid, be careful
that water does not enter the reservoir.
Water will significantly lower the boiling
point of the brake fluid and could cause
vapor lock.
ECA13540
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.
5. Bleed:
• Brake system
Refer to "BLEEDING THE BRAKE SYS-
TEM" on page 3-21.
6. Check:
• Brake fluid level
The minimum level mark "a" or below 
Add.
Refer to "CHECKING THE BRAKE FLUID
LEVEL" on page 3-26.
a
7. Check:
• Brake pedal operation
A softy or spongy feeling  Bleed the brake
system.
Refer to "BLEEDING THE BRAKE SYS-
TEM" on page 3-21.
EAS1SM1157
REMOVING THE REAR BRAKE MASTER
CYLINDER
TIP
Before removing the rear brake master cylin-
der, drain the brake fluid from the entire brake
system.
1. Remove:
• Union bolt
• Copper washers
• Brake hose
TIP
To drain any remaining brake fluid, place a con-
tainer under the master cylinder and the end of
the brake hose.
CHECKING THE REAR BRAKE MASTER EAS1SM1158
CYLINDER
1. Check:
• Brake master cylinder "1"
Damage/scratches/wear  Replace.
• Brake fluid delivery passages "2"
(brake master cylinder body)
Obstruction  Blow out with compressed
air.
1
2. Check:
• Brake master cylinder kit
Damage/wear  Replace.
3. Check:
• Master cylinder reservoir cap
Crack/damage  Replace.
• Brake master cylinder reservoir diaphragm
holder
• Brake master cylinder reservoir diaphragm
Crack/damage  Replace.
4. Check:
• Brake hoses
Cracks/damage/wear  Replace.
EAS1SM1159
4-28
REAR BRAKE
2