14. HYDRAULIC BRAKE

Page 14-0

Page 14-1

Service Information	14-1
Troubleshooting	14-2
Brake Fluid Replacement/Bleeding	14-3
Brake Pads/Disks	14-5
Front Master Cylinder	14-8
Front Brake Caliper	14-11
Rear Brake Master Cylinder	14-13
Rear Brake Caliper	14-15
Brake Pedal	14-17

SERVICE INFORMATION

GENERAL

WARNING

A contaminated brake disk or pad reduces stopping power. Discard contaminated pads and clean a contaminated disk with a high quality brake degreasing agent.
Use only DOT 4 brake fluid.
The brake and brake pads can be removed without disconnection the hydraulic system.
Once the hydraulic system has been disassembled, or if the brakes feel spongy, the system must be bled.
Do not allow foreign material to enter the system filling the reservoir.
Brake fluid will damage painted, plastic and rubber parts. Whenever handling brake fluid protect the painted, plastic and rubber paper's by covering them with a shop towel. If fluid does get on these parts, wipe it off immediately with a clean cloth.
Always check brake operation before riding the motorcycle.
Inhaled asbestos fibers have been found to cause respiratory disease and cancer. Never use an air hose or dry brush to clean brake assemblies. Use an OSHA-approved vacuum cleaner or alternate method approved by OSHA, designed to minimize the hazard caused by airborne asbestos fibers.

SPECIFICATIONS

unit: mm (in)

ITEM		STANDARD	SERVICE LIMIT
Brake Disk	Thickness	5.0 (0.19)	4.0 (0.16)
Brake Disk	Warpage	----	0.3 (0.01)
Master Cylinder I.D.	Front	12.700-12.743 (0.500-0.5016)	12.76 (0.502)
Master Cylinder I.D.	Rear	12.700-12.743 (0.500-0.5016)	12.76 (0.502)
Master piston O.D.	Front	12.657-12.684 (0.4983-0.4993)	12.65 (0.498)
Master piston O.D.	Rear	12.657-12.684 (0.4983-0.4993)	12.65 (0.498)
Caliper cylinder ID	Front	30.230-30.280 (1.1902-1.1921)	30.29 (1.193)
Caliper cylinder ID	Rear	38.180-38.230 (1.5031-1.5051)	38.24 (1.505)
Caliper piston OD	Front	30.148-30.198 (1.1870-1.1889)	30.14 (1.187)
Caliper piston OD	Rear	38.115-38.148 (1.5005-1.5018)	38.11 (1.500)
Brake Fluid		DOT 4 only	----

Page 14-2

TORQUE VALUES

Front master cylinder holder bolt	12 N-m (1.2 kg-m, 9 ft-lb)
Rear master cylinder mounting bolt	12 NM (1.2 kg-m, 9 ft-lb)
Brake oil bolt	30 NM (3.0 kg-m, 22 ft-lb)
Brake reservoir screw	1.5 NM (0. 15 kg-m, 1.4 ft-lb)
Caliper bleed valve	6 NM (0.6 kg-m, 4.3 ft-lb)
Front caliper mounting bolt	27 NM (2.7 kg-m, 20 ft-lb)
Front caliper pin bolt	28 NM (2.8 kg-m, 20 ft-lb)
Rear caliper mounting bolt	27 NM (2.7 kg-m, 20 ft-lb)
Rear caliper pivot bolt	22 NM (2.2 kg-m, 16 ft-lb)
Rear caliper pad pin	17 NM (1.7 kg-m, 12 ft-lb)
Caliper pad pin plug	2.5 NM (0.25 kg-m, 1.8 ft-lb)
Torque rod bolt	35 NM (3.5 kg-m, 25 ft-lb)
Front disc retaining bolt	40 NM (4.0 kg-m, 29 ft-lb) Apply a locking agent to the threads.
Rear disc retaining bolt	35 NM (3.5 kg-m, 25 ft-lb)
Rear disc retaining bolt lock nut	9 NM (0.9 kg-m, 7 ft-lb)

TOOL
Special Snap ring pliers	07914-3230001

TROUBLESHOOTING

Brake lever/pedal soft or spongy
• Air in hydraulic system
• Low fluid level
• Hydraulic system leaking

Brake lever/pedal too hard
• Sticking piston(s)
• Clogged hydraulic system
• Pads glazed or worn excessively

Brake drag
• Hydraulic system sticking
• Sticking piston(s)
• Clogged hydraulic system
• Incorrect pedal adjustment
• Caliper slide pins sticking
• Disc or wheel misaligned

Brakes grab
• Pads contaminated
• Disc or wheel misaligned

Brake chatter or squeal
• Pads contaminated
• Excessive disc runout
• Caliper installed incorrectly

Page 14-3

BRAKE FLUID REPLACEMENT/ AIR BLEEDING

CAUTION

Be careful not to allow dust or water to enter the brake system when filling the reservoir.

USE ONLY DOT 4 BRAKE FLUID

Do not mix different types of fluid since they are not compatible.

Avoid spilling fluid on painted surfaces. Place a rag over the fuel tank whenever the system is serviced.

Check the fluid level with the reservoir parallel to the ground.
Remove the reservoir cover, set plate and diaphragm.

BRAKE FLUID DRAINING

Connect a bleed hose to the bleed valve.

Loosen the caliper bleed valve and pump the brake lever. Stop operating the lever when fluid stops flowing out of the bleed valve.

BRAKE FLUID FILLING

NOTE:

Check the fluid level often while bleeding the brakes to prevent air from being pumped into the system.

When using the Brake Bleeder, follow the manufacturer's instructions.

Do not mix brake fluid types and never reuse the fluid which has been bled out of the system; it may impair the efficiency of the brake system.

Close the bleed valve; fill the reservoir with DOT 4 brake fluid to the upper level.

Install the diaphragm and reservoir cover.

Page 14-4

Connect a Brake Bleeder or equivalent to the bleed valve.

Pump the brake bleeder and loosen the bleed valve. Add fluid when the fluid level in the master cylinder reservoir is low. Repeat above procedures until no air bubbles appear in the plastic hose.

NOTE:

If air is entering the system from around the bleed valve threads, seal the threads with teflon tape.

If a brake bleeder is not available, fill the system as follows:

Pump up the system pressure with the lever or pedal until there are no air bubbles in the fluid flowing out of the reservoir hole and lever or pedal resistance is felt.

AIR BLEEDING

Bleed the system as follows:
1) Connect a bleed hose to the bleed valve.
2) Squeeze the brake lever (or depress the brake pedal), then open the bleed valve 1/4 turn and close the valve.

NOTE:

Do not release the brake lever (or pedal) until the bleed valve has been closed.

3) Release the brake lever (or pedal) slowly and wait several seconds after it reaches the end of its travel.
Repeat steps 2 and 3 until bubbles cease to appear in the fluid at the end of the hose.
Tighten the bleed valve.

TORQUE: 6 NM (0.6 kg-m, 4.3 ft-lb)

Close the bleed valve, fill the reservoir with DOT 4 brake fluid to the upper level.

Reinstall the diaphragm and reservoir cover.

WARNING

A contaminated brake disc or pad reduces stopping power. Discard contaminated pads and clean a contaminated disc with a high quality brake degreasing agent.

Page 14-5

BRAKE PADS/DISCS

FRONT BRAKE PAD REPLACEMENT

WARNING

Inhaled asbestos fibers have been found to cause respiratory disease and cancer. Never use an air hose or dry brush to clean brake assemblies. Use an OSHA-approved vacuum cleaner or alternate method approved by OSHA designed to minimize the hazard caused by airborne asbestos fibers.

NOTE:

Always replace the brake pads in pairs to assure even disc pressure.

'88 Only:
Remove the cotter pin.

'88 and After '88:
Remove the pad pin plug and loosen the pad pin.

Push the pistons all the way in to allow installation of new brake pads.

NOTE:

Check the brake fluid level in the reservoir as this operation causes the level to rise.

Pull the pad pin out of the caliper and remove the brake pads.

Insert the new brake pads.
Install the pad pin by pushing the pads against the caliper to depress the pad spring.

Tighten the pad pin.

TORQUE: 17 NM (1.7 kg-m, 12 ft-lb)

Install the pad pin plug.

TORQUE: 2.5 NM (0.25 kg-m, 1.8 ft-lb)

Page 14-6

'88 Only:
Install the new cotter pin onto the pad pin.

NOTE

Operate the brake lever to seat the caliper pistons against the pads.

REAR BRAKE PAD REPLACEMENT

NOTE

Always replace the brake pads in pairs to assure even disk pressure.

Remove the pad pin plug.

Loosen the pad pin.

Remove the caliper pivot bolt.

Swing the brake caliper from the brake disk
Pull the pad pin out of the caliper.
Remove the brake pads.

Page 14-7

Position the pad spring in the caliper as shown.

Push the piston all the way in to allow installation of new brake pads.

NOTE

Check the brake fluid level in the reservoir as this operation causes the level to rise.

Insert the new brake pads.
Install the pad by pushing the pads against the caliper to depress the pad spring.

Install the caliper into the brake disk so the disk is positioned between the pads, being careful not to damage the pads.

Install the caliper pivot bolt and tighten it.

TORQUE: 22 N.m (2.2 kg-m, 16 ft-lb)

Tighten the pad pin.

TORQUE: 17 N.m (1.7 kg-m, 12 ft-lb)

Install the pad pin plug.

TORQUE: 2.5 N.m (.25 kg-m, 1.8 ft-lb)

Page 14-8

DISC THICKNESS

Measure the thickness of each disc.

SERVICE LIMITS: Front: 4.0 mm (0.16 in)
Rear: 4.0 mm (0.16 in)

Brake disc removal is referred to: Front: page 12-18. Rear: page 13-11.

BRAKE DISC WARPAGE

Measure the brake discs for warpage with a dial indicator as shown.

SERVICE LIMIT: Front/Rear: 0.30 mm (0.012 in)

FRONT MASTER CYLINDER

REMOVAL

Drain brake fluid from the hydraulic system.
Remove the rear view mirror from the master cylinder and disconnect the brake light switch wires.
Disconnect the brake hose by removing the oil bolt and sealing washers.

CAUTION

Avoid spilling brake fluid on painted surfaces. Place a rag over the fuel tank whenever the brake system is serviced.

NOTE

When removing the oil hose bolt, cover the end of the hose to prevent contamination. Secure the hose to prevent fluid from leaking out.

Remove the master cylinder holder bolts and holder, then remove the master cylinder from the handlebar.

DISASSEMBLY

Remove the brake lever and brake light switch.

Page 14-9

Remove the boot.

Remove the piston and spring by removing the snap ring.

TOOL:

Snap ring pliers

07914-3230001 or equivalent commercially available in U. S. A.

Clean the inside of the master cylinder, reservoir, spring and piston with clean brake fluid.

INSPECTION

Measure the master cylinder ID
SERVICE LIMIT: 12.76 mm (0.502 in)

Check the master cylinder for scores, scratches or nicks.

Measure the master piston OD at the location shown.
SERVICE LIMIT: 12.65 mm (0.498 in)

Check the primary and secondary cups for damage before assembly.

ASSEMBLY

CAUTION

Handle the master cylinder piston, cylinder and spring as a set.

Coat all parts with clean brake fluid before assembly.
Install the spring in the master cylinder with its large diameter facing inside.
Install the piston.

CAUTION

When installing the piston, do not allow the cup lips to turn inside out.

Page 14-10

Install the snap ring using a snap ring pliers. Install the boot. CAUTION Be certain that the snap ring is seated firmly in the groove. TOOL:
Snap ring pliers	07914-3230001 or equivalent commercially available in U.S.A.
Install the brake lever and brake light switch.
INSTALLATION Set the master cylinder onto the handlebar with the holder "UP" mark facing up. Temporarily install the holder bolts. Align the slit of the master cylinder with the punch mark on the handlebar. Tighten the upper bolt first, then the lower bolt. Connect the brake light switch wires to the switch terminals. Install the rear view mirror. Connect the brake hose with the oil bolt and two sealing washers and tighten the oil bolt. TORQUE: 30 NM (3.0 kg-m, 22 ft-lb)
Fill the reservoir with DOT 4 brake fluid to the casting ledge and bleed the brake system (page 14-4). Operate the brake lever to seat the caliper pistons against the pads.

Page 14-11