14. Honda CB 750 K7 - HYDRAULIC BRAKE

~HONDA HYDRAULIC BRAKE 14.

~ CB750

TROUBLESHOOTING 14-1
SERVICE INFORMATION 14-2
BRAKE FLUID REPLACEMENT/BRAKE BLEEDING 14-3
FRONT BRAKE PAD REPLACEMENT 14-5
FRONT BRAKE CALIPER 14-8
FRONT BRAKE MASTER CYLINDER 14-14
REAR BRAKE PAD REPLACEMENT -F-MODEL 14-16
REAR BRAKE CALIPER -F-MODEL 14-17
REAR BRAKE MASTER CYLINDER 14-20

TROUBLESHOOTING Brakes Grab or Pull to One Side
1. Pads contaminated
Brake lever/Pedal Soft or Spongy 2. Defect in one side of front braking system
1. Air bubblers in hydraulic system 3. Disc or wheel misaligned
2. Insufficient fluid in hydraulic system
3. External leak in hydraulic system Brakes Chatter or Squeal
4. Internal leak in hydraulic system 1. Pads contaminated
2. Excessive runout on disc (s)
Brake Lever/Pedal Too Hard 3. Caliper installed incorrectly
1. Frozen piston (s) 4. Disc or wheel misaligned
2. Clogged hydraulic system
3. Pads glazed or worn excessively

Brake Drag
1. Hydraulic system sticking
2. Incorrect adjustment of lever or pedal
3. Frozen piston (s)

14-1

HYDRAULIC BRAKE ~ HONDA
~ CB750

SERVICE INFORMATION

WORKING .PRACTICE

The front and rear brakes can be removed without disconnecting the hydraulic system. Once the hydraulic systems
have been opened, or if the bakes feel spongy, the system must be bled. Do not allow foreign material to enter the
system when filling the reservoirs. Avoid spilling brake fluid on painted surfaces or instrument lenses, as severe
damage will result.

TOOLS

CIRCLIP PLIERS 07914-3230001
FLAT NUT WRENCH 07921-0010000

TORQUE VALUES

FRONT BRAKE CALI PER SET BOLTS 3.0-4.0 kg-m (21.6969-28.9270 ft-lbs)
FRONT BRAKE CALIPER BOLTS 3.0-4.0 kg-m (21.6969-28.9280 ft-lbs)
REAR BRAKE CALI PER BOLTS 2.4-3.0 kg-m (17.3568-21 .6969 ft-lbs)
REAR BRAKE TORQUE LINK BOLT 1.8-2.5 kg-m (13.0176-18.0800 ft-lbs)
BRAKE OIL HOSE JOINT BOLT 2.5-3.5 kg-m (18.0800-25.3129 ft-lbs)

SPECIFICATIONS

Item Standard Service Limit
Front master cylinder Cylinder I.D.
F-model 17.460-17.503 mm (0.6874-0.6891 in) 17.515 mm (0.6896 in)
K-model 14.000-14.043 mm (0.5512-0.5529 in) 14.055 mm (0.5533 in)

Piston O.D. F-model 17.417-17.444 mm (0.6857-0.6868 in) 17.405 mm (0.6852 in)
K-model 13.957-13.984 mm (0.5495-0.5506 in) 13.945 mm (0.5490 in)

Front caliper Cylinder I.D. F-model 38.180-38.230 mm (1 .5031-1.5051 in) 38.240 mm (1.5055 in)
K-model 42.850-42.900 mm (1.6870-1 .6890 in) 42.915 mm (1 .6896 in)

Piston O.D. F-model 38.098-38.148 mm (1.4999-1.5019 in) 38.090 mm (1.4996 in)
K-model 42.805 mm (1.6852 in)
42.820mm (1.6858 in)
17.515 mm (0.6896 in)
Rear master cylinder Cylinder I.D. 17.460-17.503 mm (0.6874-0.6891 in) 17.405 mm (0.6852 in)
Piston O.D. 17.417-17.444 mm (0.6857-0.6868 in)
32.240 mm (1.5055 in)
Rear caliper Cylinder I.D. 38.180-38.230 mm (1 .5031-1.5051 in) 38.090 mm (1 .4996 in)
Piston O.D. 38.098-38.148 mm (1.4999-1.5019 in)

14-2

~HONDA HYDRAULIC BRAKE

~ CB750

BRAKE FLUID (3) HONDA BRAKE FLUID DOT-3
REPLACEMENT/AIR
BLEEDING

Check the fluid level with the fluid reservoir
parallel with the ground.

ICAUTION

• Be sure to install the diaphragm on the
reservoir when operating the brake lever.
Failure to do so will force the fluid out of
the reservoir by the system pressure
pumped up by the operation of the brake
lever

• Avoid spilling fluid on painted surfaces.
Place a rag over the fuel tank whenever

r the system is serviced.

BRAKE FLUID DRAINING

Remove the bleeder valve dust cap.

Connect a bleed hose and place one end in a
clean container.

Loosen the caliper bleeder valve and pump up
the system pressure by operating the brake
lever/pedal. Stop operating the lever/pedal
when no fluid is flowing out of the bleeder
valve.

BRAKE FLUID FILLING (2) BLEEDER VALVE

ICAUTION (3) NEVER RE-USE

• Check the fluid level often while bleeding 14-3
the brake, to prevent air from being
pumped into the system.

• Do not mix different brands of fluid since
they are not compatible .

Close the bleeder valve, fill the reservoir, and
install the diaphragm.

To prevent piston overtravel and brake fluid
seepage, keep a 20 mm space to the handlebar
grip when bleeding the front brake system .

Pump up the system pressure with the
leve/ pedal until there are no air bubbles in the
fluid flowing out of the reservoir small hole
(until the lever/ pedal becomes hard) .

HYDRAULIC BRAKE ~ HONDA
~ CB750

AIR BLEEDING (FRONT) (1) HONDA BRAKE FLUID DOT-3
· ~ - - (2) DIAPHRAGM
Pull the brake lever all the way back to the
handlebar ·grip. Screw out the bleeder valve
about 1/2 turn, and retighten.

NOTE
Do not release the lever until the bleeder
valve has been closed.

Release the lever gradually and wait for several
seconds after it reaches the end of its travel.
Repeat the above steps until there is no air
bubble in the fluid flowing out of the bleeder
valve .

Fill the reservoir up to the UPPER FLUID
LEVEL.

Check the entire system for leaks by operating
the lever.

A contaminated brake disc or pad reduces (6) VINYL TUBE
stopping power. Replace contaminated
pads, and clean a contaminated disc with a (5) ABOUT 20mm
good quality degreasing agent.

AIR BLEEDING (REAR) (F-MODEL)

Depress the brake pedal all the way. Screw out
the bleeder valve about 1/2 turn, and retighten.

NOTE
Do not release the brake pedal until the
bleeder valve has been closed.

Release the pedal gradually and wait for several
seconds after it reaches the end of its travel.
Repeat the above steps until there is no air
bubble in the fluid flowing out of the bleeder
valve .

Fill the reservoir up to the UPPER FLUID
LEVEL.

Avoid spilling fluid on painted surfaces. Do
not mix different brands of fluid since they
are not compatible.

14-4

~HONDA HYDRAULIC BRAKE

~ CB750

BRAKE PAD
REPLACEMENT

F-MODEL

The front brake pads require replacement if
the red line on the top of the pads reaches
the edges of the brake disc.

Remove the caliper bolts.

Remove the brake caliper, pads and shims.

NOTE
Do not operate the brake lever to prevent
piston overtravel and brake fluid seepage
during disassembly.

Install new pads and shims.

NOTE

"+"Install the shims with the mark

facing up. Push the piston all the way in,
and torque the caliper bolts.

TORQUE: 2.4-3.0kg-m 117.4-21.7 ft-lbsl

14-5

HYDRAULIC BRAKE W\HONDA

BRAKE PAD REPLACEMENT ~ CB750
K-MODEL

The front bfc;!ke pads require replacement if
the red line on the top of the pads reaches
the edge of the brake disc.

Free the brake hose from the fender clip. A B
Remove the caliper bolts to remove the
caliper.
Remove the pads and wipe clean the pad
areas of the caliper with a clean rag .

NOTE
Do not operate the brake lever to prevent
piston overtravel and brake fluid seepage
during disassembly.

Apply silicon grease to the pads A and B and
caliper before assembly .

14-6

~HONDA HYDRAULIC BRAKE

~ CB750

Loosen the lock nut and screw out the caliper
adjusting bolt fully.

Insert the brake hose into the fender clip,
install the pads A and B, and tighten the
caliper bolts.
TORQUE: 0.8-1.2 kg-m (5.8-8.7 ft·lbs)

With the front wheel off the ground, screw in
the adjusting bolt until the pad B contacts the
brake disc, then screw out 1/2 turn. Tighten
the lock nut.

14-7

HYDRAULIC BRAKE ~HONDA

FRONT BRAKE ~ CB750
CALIPER-F MODEL
' (31PISTON
CALIPER REMOVAL 141BOOT

Drain brake fluid from the brake hydraulic
system (Page 14-3).
Disconnect the brake hose.

CAUTION
Avoid spilling brake fluid on painted sur-
faces.

Remove the brake caliper.

CALIPER DISASSEMBLY

Remove the brake pad spring .
Remove the boot clip and remove the boot.

(5)B 00T RIN G- - - - - 1 1 -

Place a shop towel or rag over the piston to
prevent the piston from coming out, and
position the caliper with the piston down.

Apply a small amount of air pressure to the
fluid outlet, to remove the piston .

Do not use high pressure air or bring the
nozzle too close to the inlet.

14-8

~HONDA HYDRAULIC BRAKE
~ CB750

Remove the piston seal.

NOTE
Remove the piston seal from the caliper
by lifting it out.

PISTON 0.0. INSPECTION

Check the piston for scoring, scratches, nicks
or other defects and replace if necessary.
SERVICE LIMIT: 38.09 mm 11.4996 in .)

CYLINDER INSPECTION

Check the cylinder for scoring, scratches or
other defects and replace if necessary.
SERVICE LIMIT: 38.24 mm (1.5055 in.)

Remove the caliper bracket.
Remove the pin.

INOTE
Do not damage the boot.

14-9

HYDRAULIC BRAKE ~HONDA

CALIPER ASSEMBLY ~ CB750

Assembly of the brake caliper is essentially the
reverse of disassembly.

Install a new piston seal in the groove in the
cylinder and apply a thin coating of silicon
grease to it. Install the piston in the cylinder.
Install the piston boot and clip. Install the
brake pad spring.

!NOTE
Note the pad spring direction.

/

Install the brake caliper and tighten the bolts.
TORQUE: ;3.0-4.0kg-m (21.7-28.9 ft-lbs)
Install the brake hose.
Bleed the system.

14-10

~HONDA HYDRAULIC BRAKE

~ CB750

BRAKE CALIPER REMOVAL
K-MODEL

Drain the brake fluid from the system.
Disconnect the brake hose (Page 14-3).

BRAKE CALIPER DISASSEMBLY (1) FENDER
(2) LEFT FRONT FORK

(9) SPLIT PIN

(10) PAD B (8) PAD A (4)TO REMOVE AND INSTALL, USE
(7) PISTON FLAT NUT WRENCH

07921-0110000

~LTS(A)

@~

(6) SILICON GREASE

14-11

HYDRAULIC BRAKE ~HONDA

PISTON 0.0. INSPECTION ~ CB750

Examine the piston for scoring, scratches or any
other defects and replace if necessary.

SERVICE LIMIT: 42.805 mm (1.6852 In.)

CYLINDER 1.0. INSPECTION

Check the cylinder for scoring, scratches or any
other defects and replace if necessary.

SERVICE LIMIT: 42.915 mm (1.6896 In.)

/

BRAKE CALIPER ASSEMBLY

Before assembling the brake caliper, apply
grease to the sliding face of the caliper holder
pin.

14-12

~HONDA HYDRAULIC BRAKE

~ CB750

Install a new piston seal. Coat the piston with
silicon grease and install it.

NOTE

! Insert the piston fully.

Apply silicon grease to the brake pads and
install .

( !)PISTON SEAL

Install the caliper and torque the bolts.

TORQUE: 3.0-4.0 kg-m (21.7-28.9ft-lbs)
Insert the brake hose into the fender clip and
connect the hose to the brake caliper fitting.

Adjust the returning of the caliper with the
caliper adjusting bolt (page 14-7) .

Bleed the system.

14-13

HYDRAULIC BRAKE ~ HONDA

FRONT BRAKE ~ CB750
MASTER CYLINDER

DISASSEMBLY

Drain the brake hydraulic system.

Disconnect the brake hose.

NOTE
When removing the oil bolt, cover the end
of the hose to prevent contamination and
secure the hose to the fork.

CAUTION
Avoid spilling brake fluid on painted

surfaces.

Remove the brake lever.

Remove the master cylinder.

Remove the circlip from the master cylinder
body.

Remove the stop plate, secondary cup and 'T MASTER CYLINDER BODY
piston. Remove the primary cup, spring and
check valve. (2)SPRING
It may be necessary to apply a small amount (3)PRIMARY CUP
of air pressure to the fluid outlet to remove
the piston and primary cup. (4)PISTON
(S)SECONDARY CUP
( l )FRONT MASTER
(6)STOP PLATE
14-14
·lr lRCLIP

- ---:t'~.._· (8)B00T
-~

~HONDA HYDRAULIC BRAKE
~ CB750

MASTER CYLINDER 1.D.
INSPECTION

Check the master cylinder for scoring, scrat-
ches, nicks or other defects.

SERVICE LIMIT:
F-MODEL: 17.515 mm (0.689 in.)
K-MODEL: 14.055 mm (0.553 in.)

MASTER PISTON O.D. IN-
SPECTION

Measure the master piston O.D.

SERVICE LIMT:
F MODEL: 17.405 mm (0.685 in.)
K MODEL: 13.945 mm (0.549 in.I

MASTER CYLINDER ASSEMBLY

Reassemble the master cylinder in the reverse
order of disassembly. Coat all parts with clean
brake fluid before assembly. Install the check
valve on the spring. Install the spring and
valve together.

CAUTION I

When installing the cups, do not allow the
lips to turn inside out. Be certain the circlip is
seated firmly in the groove.

After reassembling, fill the reservoir to the
UPPER LEVEL and bleed the brake system
(Page 14-3).

14-15

HYDRAULIC BRAKE ~HONDA

REAR BRAKE PAD ~ CB750
REPLACEMENT-

F-MODEL

The rear brake pads require replacement if the
red line on the top of the pads reaches the
edges of the brake disc.

Remove the caliper set bolts.
Remove the caliper, brake pads and shims.

NOTE
Do not operate the brake pedal while
disassembling the rear brake.

Install new pads and shims.
NOTE
Install the shims with the mark ...... facing
up .

Insert the piston into the cylinder fully .
Install the caliper and torque the bolts.
TORQUE: 2.4-3.0 kg-m (17.4-21.7 ft-lbs)

14-16

~HONDA HYDRAULIC BRAKE

~ CB750

REAR BRAKE
CALIPER

CALIPER REMOVAL

Drain brake fluid from the hydraulic system .
Disconnect the brake hose.

CAUTION]
• Avoid spilling brake fluid on painted

surfaces.
• Place a rag over the fuel tank whenever

the brake system is serviced.
• Remove the calipers.

CALIPER DISASSEMBLY , . - - -( l )CALIPER ·
(2)P1ST0N SEAL
Remove the brake pad spring. (3)P1ST0N
Remove the clip and then take out the boot.
(4)B00T

Remove the piston by applying a small
amount of air pressure to the fluid outlet.

Place a shop towel or rag over the piston to
prevent the piston from coming out, and
position the caliper with the piston down.

Do not use high pressure air or bring the
nozzle too close to the inlet.

14-17

HYDRAULIC BRAKE ~HONDA

Remove the piston seal. ~ CB750

NOTE
lift out thll piston seal by first pushing it
into the cylinder as shown.

PISTON O.D. INSPECTION 1.8-2.5 kg-m

Examine the piston for scoring, scratches, nicks (13.0-18.1 ft-lbs)
or other defects and replace if necessary.
SERVICE LIMIT: 38.090 mm (1.4996 in.I ,6'1°~~~~

CALIPER CYLINDER I.D. IN-
SPECTION

Check the caliper cylinder for scoring, scratches
or nicks and replace if necessary.
SERVICE llMIT: 38.240 mm (1.5055 In.)

Remove the brake torque link.
Pry off the cotter pin and loosen the axle nut.
Loosen the drive chain adjusters and withdraw
the axle. Remove the caliper bracket.
Remove the pin.

NOTE
Do not damage the boot.

14-18

~HONDA HYDRAULIC BRAKE
~ CB750

ASSEMBLY 1.8-2.Skg-m
(13.0-18.1 ft-lbs)
Assembly is the reverse order of disassembly.
,~"~~~

Coat the caliper pins with silicon grease and
install into the caliper.

NOTE
Align the flats on the pins with the cutouts
in the caliper.

Install the piston seal in the groove in the caliper
cylinder. Apply silicon grease to the piston and
insert the piston into the cylinder.

!NOTE
insert the piston into the cylinder fully.

Install the boot and boot clip .
Install the pad spring.

NOTE

!Note the pad spring direction.

14-19

HYDRAULIC BRAKE ~HONDA
~ CB750

REAR BRAKE (2)COTIER PIN
MASTER CYLINDER (3) ALIGN PUNCH MARKS

MASTER CYLINDER REMOVAL

Remove the right side cover.

Drain brake fluid from the brake hydraulic
system.

Disconnect the brake hose.

Pry off the cotter pin and remove the brake rod
joint.

Remove the reservoir and master cylinder.

., MASTER CYLINDER DISASSEMBLY

Disconnect the brake rod joint and remove the
boot.

Remove the circlip and take out the piston
spring.

Remove the piston, primary cup, spring and ( l)MASTER
check valve.
CUP
NOTE
It may be necessary to apply a small
amount of air pressure to the fluid outlet
to remove the piston and primary cup.

(6)PUSH

~t't··(7)STOP PLATE
(8)CIRCLI P

14-20

~HONDA HYDRAULIC BRAKE
~ CB750

PISTON 0.D. INSPECTION

Measure the piston diameter. Inspect the
condition of the primary and secondary cups.
SERVICE LIMIT : 17.405 mm (0.68521n.)

MASTER CYLINDER 1.D. INSPECTION

Measure the master cylinder 1.0.
SERVICE LIMIT : 17.515 mm (0.6898 In.)

MASTER CYLINDER ASSEMBLY (l)MASTER

Coat all parts with clean brake fluid before
assembly. Install the check valve on the spring.
install the spring and valve as a unit.

ICAUTION

When installing the cups, do not allow the
lips to turn inside out.
Be certain that the snap ring is seated in the
groove firmly.

Install the primary cup and piston.
Install the push rod and circlip.
Install the boot, nut and rod eye.
Place the master cylinder in position on the
motorcycle and install the mounting bolts, rod
eye pin, washer and cotter pin. Then install the
brake line.
Fill the reservoir to the UPPER LEVEL and bleed
the brake system (Page 14-4).
Adjustthe brake pedal height (Page3-14).

14-21