Yamaha YZ 2023 Series, Owner'S Service Manual

Page: 147 / 378

REAR BRAKE
4-33
TIP
Install the spring with a smaller inside diameter
to the brake master cylinder piston.
4. Install:
•
Brake master cylinder piston assembly “1”
• Push rod “2”
•
Circlip “3”
•
Dust boot “4”
TIP
• Always install new brake master cylinder kit
“5”.
• Before installation, apply brake fluid to the
brake master cylinder piston assembly.
• Before installation, apply silicone grease to the
push rod end.
• Before installation, apply brake fluid to the in-
side of the brake master cylinder.
EAM30051
INSTALLING THE REAR BRAKE MASTER
CYLINDER
1. Install:
•
Copper washer
• Brake hose
•
Union bolt
WARNING
EWA13531
Proper brake hose routing is essential to in-
sure safe vehicle operation.
NOTICE
ECA24500
Make sure that the pipe portion of the brake
hose touches the projection “a” on the brake
caliper.
2. Pour brake fluid to the brake fluid reservoir up
to the specified level.
WARNING
EWA13090
• 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 fluids
may result in a harmful chemical reaction,
leading to poor brake performance.
• When refilling, be careful that water does
not enter the brake fluid reservoir. Water
will significantly lower the boiling point of
the brake fluid and could cause vapor lock.
NOTICE
ECA24510
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean up
any spilt brake fluid immediately.
3. Bleed:
• Brake system
Refer to “BLEEDING THE HYDRAULIC
BRAKE SYSTEM” on page 3-25.
4. Check:
• Brake fluid level
The minimum level mark or below

Add.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-23.
5. Check:
•
Brake pedal operation
A softy or spongy feeling

Bleed the brake
Brake hose union bolt
30 N·m (3.0 kgf·m, 22 lb·ft)
1
2
5
New
1
3
4
2
Ne w
T
R
.
.
Specified brake fluid
DOT 4
a