Yamaha XMAX YP125R - Service manual > Front brake

Removing the front brake pads

Removing the front brake master cylinder

Disassembling the front brake master cylinder

Removing the front brake caliper

Disassembling the front brake caliper

Introduction

WARNING

Disc brake components rarely require disassembly.

Therefore, always follow these preventive measures:

• Never disassemble brake components unless absolutely necessary.
• If any connection on the hydraulic brake system is disconnected, the entire brake system must be disassembled, drained, cleaned, properly filled, and bled after reassembly.
• Never use solvents on internal brake components.
• Use only clean or new brake fluid for cleaning brake components.
• Brake fluid may damage painted surfaces and plastic parts. Therefore, always clean up any spilt brake fluid immediately.
• Avoid brake fluid coming into contact with the eyes as it can cause serious injury.

FIRST AID FOR BRAKE FLUID ENTERING THE EYES:

• Flush with water for 15 minutes and get immediate medical attention.

Checking the front brake disc

1. Remove:

• Front wheel

2. Check:

• Brake disc

Damage/galling → Replace.

3. Measure:

• Brake disc deflection

Out of specification → Correct the brake disc deflection or replace the brake disc.

Brake disc deflection limit 0.15 mm (0.0059 in)

a. Place the vehicle on a suitable stand so that the front wheel is elevated.

b. Before measuring the front brake disc deflection, turn the handlebar to the left or right to ensure that the front wheel is stationary.

c. Remove the brake caliper.

d. Hold the dial gauge at a right angle against the brake disc surface.

e. Measure the deflection 1.5 mm (0.06 in) below the edge of the brake disc.

4. Measure:

• Brake disc thickness

Measure the brake disc thickness at a few different locations.

Out of specification → Replace.

Brake disc thickness limit 4.5 mm (0.18 in)

5. Adjust:

• Brake disc deflection

a. Remove the brake disc.

b. Rotate the brake disc by one bolt hole.

c. Install the brake disc.

Front brake disc bolt 12 Nm (1.2 m*kgf, 8.7 ft*lbf) LOCTITE

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.

6. Install:

• Front wheel

Replacing the front brake pads

TIP

When replacing the brake pads, it is not necessary to disconnect the brake hose or disassemble the brake caliper.

1. Measure:

• Brake pad wear limit "a"

Out of specification → Replace the brake pads as a set.

Brake pad lining thickness (inner) 5.0 mm (0.20 in)

Limit 1.5 mm (0.06 in)

Brake pad lining thickness (outer) 5.0 mm (0.20 in)

Limit 1.5 mm (0.06 in)

2. Install:

• Brake pad support
• Brake pad spring
• Brake pads

TIP

Always install new brake pads, a new brake pad spring, and a new brake pad support as a set.

a. Connect a clear plastic hose "1" tightly to the bleed screw "2". Put the other end of the hose into an open container.

b. Loosen the bleed screw and push the brake caliper pistons into the brake caliper with your finger.

c. Tighten the bleed screw.

Bleed screw 6 Nm (0.6 m*kgf, 4.3 ft*lbf)

d. Install new brake pad support, new brake pad spring and new brake pads.

3. Install:

• Brake pad pin
• Brake pad pin cap
• Front brake caliper
• Speed sensor lead guide
• Front brake caliper bolts

Front brake caliper bolt 40 Nm (4.0 m*kgf, 29 ft*lbf)

4. Check:

• Brake fluid level

Below the minimum level mark "a" → Add the recommended brake fluid to the proper level.

5. Check:

• Brake lever operation

Soft or spongy feeling → Bleed the brake system.

Removing the front brake caliper

TIP

Before removing the brake caliper, drain the brake fluid from the entire brake system.

1. Remove:

• Brake hose union bolt "1"
• Copper washers "2"
• Front brake hose "3"

TIP

Put the end of the brake hose into a container and pump out the brake fluid carefully.

Disassembling the front brake caliper

1. Remove:

• Brake caliper pistons "1"
• Brake caliper piston dust seals "2"
• Brake caliper piston seals "3"

a. Blow compressed air into the brake hose joint opening "a" to force out the pistons from the brake caliper.

WARNING

• Cover the brake caliper piston with a rag.

  Be careful not to get injured when the piston is expelled from the brake caliper.

• Never try to pry out the brake caliper piston.

b. Remove the brake caliper piston dust seals and brake caliper piston seals.

Checking the front brake caliper

1. Check:

• Brake caliper pistons "1"

Rust/scratches/wear → Replace the brake caliper pistons.

• Brake caliper cylinders "2"

Scratches/wear → Replace the brake caliper assembly.

• Brake caliper body "3"

Cracks/damage → Replace the brake caliper assembly.

• Brake fluid delivery passages (brake caliper body)

Obstruction → Blow out with compressed air.

WARNING

Whenever a brake caliper is disassembled, replace the brake caliper piston dust seals and brake caliper piston seals.

2. Check:

• Brake caliper bracket

Cracks/damage → Replace.

Assembling the front brake caliper

WARNING

• Before installation, all internal brake components should be cleaned and lubricated with clean or new brake fluid.
• Never use solvents on internal brake components as they will cause the brake caliper piston dust seals and brake caliper piston seals to swell and distort.
• Whenever a brake caliper is disassembled, replace the brake caliper piston dust seals and brake caliper piston seals.

Recommended fluid DOT 4

Installing the front brake caliper

1. Install:

• Front brake caliper "1" (temporarily)
• Copper washers "2"
• Front brake hose "3"
• Brake hose union bolt "4"

Front brake hose union bolt 23 Nm (2.3 m*kgf, 17 ft*lbf)

WARNING

Proper brake hose routing is essential to insure safe vehicle operation.

NOTICE

When installing the brake hose onto the brake caliper "1", make sure the brake pipe "a" touches the projection "b" on the brake caliper.

2. Remove:

• Front brake caliper

3. Install:

• Brake pad support
• Brake pad spring
• Brake pads
• Brake pad pin
• Brake pad pin cap
• Front brake caliper
• Speed sensor lead guide

Brake pad pin 18 Nm (1.8 m*kgf, 13 ft*lbf)

Brake pad pin cap 3 Nm (0.3 m*kgf, 2.2 ft*lbf)

Front brake caliper bolt 40 Nm (4.0 m*kgf, 29 ft*lbf)

4. Fill:

• Brake master cylinder reservoir (with the specified amount of the recommended brake fluid)

Recommended fluid DOT 4

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 master cylinder reservoir.

  Water will significantly lower the boiling point of the brake fluid and could cause vapor lock.

NOTICE

Brake fluid may damage painted surfaces and plastic parts. Therefore, always clean up any spilt brake fluid immediately.

5. Bleed:

• Brake system

6. Check:

• Brake fluid level

Below the minimum level mark "a" → Add the recommended brake fluid to the proper level.

7. Check:

• Brake lever operation

Soft or spongy feeling → Bleed the brake system.

Removing the front brake master cylinder

TIP

Before removing the front brake master cylinder, drain the brake fluid from the entire brake system.

1. Remove:

• Brake hose union bolt "1"
• Copper washers "2"
• Front brake hose "3"

TIP

To collect any remaining brake fluid, place a container under the master cylinder and the end of the brake hose.

Checking the front brake master cylinder

1. Check:

• Brake master cylinder

Damage/scratches/wear → Replace.

• Brake fluid delivery passages (brake master cylinder body)

Obstruction → Blow out with compressed air.

2. Check:

• Brake master cylinder kit

Damage/scratches/wear → Replace.

3. Check:

• Brake master cylinder reservoir cap
• Brake master cylinder reservoir diaphragm holder
• Brake master cylinder reservoir diaphragm Damage/wear → Replace.

4. Check:

• Front brake hose

Cracks/damage/wear → Replace.

Assembling the front brake master cylinder

WARNING

• Before installation, all internal brake components should be cleaned and lubricated with clean or new brake fluid.
• Never use solvents on internal brake components.

Recommended fluid DOT 4

Installing the front brake master cylinder

1. Install:

• Brake master cylinder "1"
• Brake master cylinder holder

Brake master cylinder holder bolt 7 Nm (0.7 m*kgf, 5.1 ft*lbf)

TIP

• Align the projection "a" on the brake master cylinder with the hole "b" in the handlebar
• First, tighten the front bolt, then the rear bolt.

2. Install:

• Copper washers "1"
• Front brake hose "2"
• Brake hose union bolt "3"

Brake hose union bolt 23 Nm (2.3 m*kgf, 17 ft*lbf)

WARNING

Proper brake hose routing is essential to insure safe vehicle operation.

NOTICE

When installing the brake hose onto the brake master cylinder, make sure the brake pipe touches the projection "a" as shown.

TIP

Turn the handlebar to the left and right to make sure the brake hose does not touch other parts (e.g., wire harness, cables, leads). Correct if necessary.

3. Fill:

• Brake master cylinder reservoir (with the specified amount of the recommended brake fluid)

Recommended fluid DOT 4

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 master cylinder reservoir.

  Water will significantly lower the boiling point of the brake fluid and could cause vapor lock.

NOTICE

Brake fluid may damage painted surfaces and plastic parts. Therefore, always clean up any spilt brake fluid immediately.

4. Bleed:

• Brake system

5. Check:

• Brake fluid level

Below the minimum level mark "a" → Add the recommended brake fluid to the proper level.

6. Check:

• Brake lever operation

Soft or spongy feeling → Bleed the brake system.

See also: