Yamaha YZ 2018 Series, Owner'S Service Manual

Page: 151 / 402

REAR BRAKE
4-25
EASB29B154
INTRODUCTION
EWA
WARNING
If you need to disassemble the disc brake
components, observe the following precau-
tions.
• Never disassemble the brake components
unless absolutely necessary.
• If there is any problem with connections
on the hydraulic brake system, perform
the following jobs.
Disassemble the brake system, drain the
brake fluid, and clean it. After that, add a
suitable amount of brake fluid. Then, bleed
it after reassembly.
• Use only brake fluid for washing internal
brake components.
• Use new brake fluid for cleaning the brake
components.
• Immediately wipe off the spilled brake fluid
to avoid damage to painted surfaces or
plastic parts.
• Handle brake fluid with special care not to
let it enter your eyes so that you may not
lost your eyesight.
• FIRST AID FOR BRAKE FLUID ENTERING
THE EYES:
• Flush with water for 15 minutes and get
immediate medical attention.
EASB29B155
CHECKING THE REAR BRAKE DISC
1. Remove:
• Rear wheel
Refer to “REAR WHEEL” on page 4-7.
2. Check:
• Brake disc
Damage/galling

Replace.
3. Measure:
• Brake disc thickness
Measure the brake disc thickness at a few
different locations.
Out of specification

Replace.
Refer to “CHECKING THE FRONT BRAKE
DISC” on page 4-15.
4. Measure:
• Brake disc deflection
Out of specification

Correct the brake disc
deflection or replace the brake disc.
5. Adjust:
• Brake disc deflection
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a. Remove the brake disc.
b. Turn the mounted position of the brake disc
by one bolt hole.
c. Install the brake disc.
TIP
Tighten the brake disc bolts in stages and in a
crisscross pattern.
d. Measure the brake disc deflection.
e. If out of specification, repeat the adjustment
steps until the brake disc deflection is within
specification.
f. If the brake disc deflection cannot be
brought within specification, replace the
brake disc.
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6. Install:
• Rear wheel
Refer to “REAR WHEEL” on page 4-7.
Brake disc thickness limit
3.5 mm (0.14 in)
Brake disc runout limit (as mea-
sured on wheel)
0.15 mm (0.0059 in)
Brake disc bolt
14 N·m (1.4 kgf·m, 10 lb·ft)
LOCTITE®
T
R
.
.