Removing The Rear Brake Master Cylinder; Checking The Rear Brake Master Cylinder - Yamaha YZ 2019 Series Owner's Service Manual

Brake pad pin
17 N·m (1.7 kgf·m, 13 lb·ft)
Brake pad pin plug
2.5 N·m (0.25 kgf·m, 1.8 lb·ft)
Refer to "CHECKING THE REAR BRAKE
PADS" on page 3-25.
4. Pour brake fluid to the brake fluid reservoir up
to the specified level.
Specified brake fluid
DOT 4
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 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.
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 SYSTEM"
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 SYSTEM"
on page 3-21.
EAM30048
REMOVING THE REAR BRAKE MASTER
CYLINDER
TIP
Before removing the rear 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.
EAM30049
CHECKING THE REAR BRAKE MASTER
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:
• Brake master cylinder reservoir cap
Crack/damage  Replace.
• Brake master cylinder reservoir diaphragm
holder
• Brake master cylinder reservoir diaphragm
Crack/damage  Replace.
4-28
REAR BRAKE
2