Removing The Front Brake Master Cylinder; Checking The Front Brake Master Cylinder; Assembling The Front Brake Master Cylinder - Yamaha YZ450FN 2022 Owner's Service Manual

Refer to "BLEEDING THE HYDRAULIC
BRAKE SYSTEM" on page 3-25.
6. Check:
• Brake fluid level
The minimum level mark or below  Add.
Refer to "CHECKING THE BRAKE FLUID
LEVEL" on page 3-23.
7. Check:
• Brake lever operation
A softy or spongy feeling  Bleed the brake
system.
Refer to "BLEEDING THE HYDRAULIC
BRAKE SYSTEM" on page 3-25.
EAM30036
REMOVING THE FRONT BRAKE MASTER
CYLINDER
TIP
Before removing the front brake master cylinder,
drain the brake fluid from the entire brake sys-
tem.
1. Remove:
• Union bolt
• Copper washer
• Brake hose
TIP
To drain any remaining brake fluid, place a con-
tainer under the master cylinder and the end of
the brake hose.
EAM30037
CHECKING THE FRONT BRAKE MASTER
CYLINDER
1. Check:
• Brake master cylinder "1"
Damage/scratches/wear  Replace the
brake master cylinder assembly.
• Brake fluid delivery passages "2"
(brake master cylinder body)
Obstruction  Blow out with compressed air.
2. Check:
• Brake master cylinder reservoir cap
Damage/scratches/wear  Replace.
1
2
3. Check:
• Brake hose
Cracks/damage/wear  Replace.
EAM30038
ASSEMBLING THE FRONT BRAKE MASTER
CYLINDER
EWA13520
WARNING
• 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.
Specified brake fluid
DOT 4
1. Wash the brake master cylinder with brake
fluid.
2. Install:
• Primary cylinder cup "1"
• Secondary cylinder cup "2"
(to the brake master cylinder piston "3")
EWA20240
WARNING
Apply brake fluid to the cylinder cups and in-
stall them as shown. Wrong orientation in in-
stallation causes poor braking performance.
1
1
3. Install:
• Spring "1"
(to the brake master cylinder piston "2")
4-21
FRONT BRAKE
2
3
2
3