Yamaha WR450F 2021, Owner'S Service Manual, Page: 159 / 402

REAR BRAKE
4-31
EAM30040
INTRODUCTION
WARNING
EWA19260
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 sys-
tem, 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 im-
mediate medical attention.
EAM30041
CHECKING THE REAR BRAKE DISC
1. Check:
• Brake disc
Damage/galling

Replace.
2. Measure:
•
Brake disc thickness
Measure the brake disc thickness at a few dif-
ferent locations.
Out of specification

Replace.
Refer to “CHECKING THE FRONT BRAKE
DISC” on page 4-20.
3. Measure:
• Brake disc runout
Out of specification

Replace the brake
disc.
Refer to “CHECKING THE FRONT BRAKE
DISC” on page 4-20.
4. Replace:
• Brake disc
Refer to “ASSEMBLING THE REAR
WHEEL” on page 4-14.
EAM30523
REPLACING THE REAR BRAKE PADS
TIP
When replacing the brake pads, it is not neces-
sary to disconnect the brake hose or disassem-
ble the brake caliper.
1. Remove:
•
Brake pad
a. Remove the protector “1” and the pad pin
plug “2”.
b. Loosen the pad pin “3”.
c. Remove the rear wheel “4” and the brake
caliper “5”.
Refer to “REAR WHEEL” on page 4-12.
d. Remove the pad pin “6” and the brake
pads “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)
1
2
1
2
3 3
5 5
4 4