2003 HONDA CIVIC Brake master cylinder

Rapid brake pad wear. Vehicle vibration {after a long
drivel, or High, hard brake pedal
1. Drive the vehicle until the brakes drag or untilthe
pedal is high and hard. This can take 20 or more
brake pedal applications during an extended test
drive.
2. With the engine running, raise the vehicle on a lift,
and spin all four wheels by hand.
ls there btake drag at any of the wheels?
YES Go to step 3.
NO Look for other causes of the pad wear, high
pedal, or vehicle vibration.I
3. Turn the engine off, pump the brake pedal to
deplete the vacuum in the brake booster, and then
spin the wheels again to check for brake drag.
ls therc brake dtag at any ot the wheels?
YES-Go to step 4.
NO Replace the brake booster.I
4. Without removing the brake lines, unbolt and
separate the master cylinder from the booster, then
spin the wheels lo check for brake drag.
ls there btake drag at any of the wheels?
YES Go to step 5,
NO-Check the brake pedal position switch
adjustment and pedal free play.I
5. Loosen the hydraulic lines at the master cylinder,
then spin the wheels to check for brake drag.
ls there brake drag at any of the wheels?
YES Go to step 6.
NO- Replace the master cylinder.l
6. Loosen the bleeder screws at each caliper, then
spin the wheels to check for brake drag.
Is there brake drag at any of the wheels?
YES Disassemble and repair the caliper on the
wheel(s) with brake drag.l
NO Inspect brake hose (s)/line (s).
19-5

Conventional Brake Components
Brake System Bleeding
NOTE:. Do not spill brake fluid on the vehicle; it may damage
the painU if brake fluid does contact the paint. wash it
off immediately with water.. The reservoir on the master cylinder must be at the
MAX (upper) level mark at the start of the bleeding
procedure and checked after bleeding each brake
caliper. Add fluid as required.. Do not reuse the drained fluid.. Always use Honda DOT 3 brake fluid. Non-Honda
brake fluid can cause corrosion and shorten the life of
the system.. Make sure no din or other foreign matter is allowed
to contaminate the brake fluid.
1. Make sure the brake fluid level in the reservoir is at
the MAX (upper) level line (A).
Slide a piece of clear plastic hose over the flrst
bleed screw, and submerge the other end in a
container of new brake fluid.
Have someone slowly pump the brake pedal
severaltimes, then apply steady pressure.
Starting at the left-front, loosen the brake bleed
screw to allow air to escape from the system. Then
tighten the bleed screw securely.
2.
19-8
5. ReDeatthe procedure for each wheel in the
sequence shown below until air bubbles no longer
appear in the fluid.
BLEEDING SEOUENCE:
OFront RightORe.r Right
O Front LeftORoar Loft
Refill the master cylinder reservoir to the MAX
{upper) level line.
FRONT BRAKE:
9 N.m 10.9 kgf.m,7 lbl.ft)
t-
REAR BRAKE:
9 N m 10.9 kgf.m, 7 lbf ft)

Master Cylinder Replacement
NOTE: Do not spill brake fluid on the vehicle; it may
damage the paint; if brake fluid does contact the paint,
wash it off immediately with water,
1, Remove the air cleaner assembly (A).
2, Disconnect the brake fluid level sensor connector
(A).
15 N.m{1.5 kgt.m, 11 lbt.ft)
3. Remove the clutch reservoir (B) andenginewire
harness clip (C)from the master cylinder mounting
base (D).
4. Remove the reservoir cap and brake fuid from the
reservoir.
5. Remove the reservoir (E) on the master cylinder
mountrng Dase.
6, Disconnect the brake lines (F)from the master
cylinder (G). To prevent spills, cover the hose joints
with rags or shop towels.
7. Remove the master cylinder mounting nuts {H) and
washers.
8. Remove the master cylinder from the brake booster.
Be careful not to bend or damage the brake lines
when removing the master cylinder.
9. Remove the rod seal (l) from the master cylinder.
10. Installthe master cylinder in the reverse order of
removal, and note these items:
. Replace all the rubber parts with new ones
whenever the master cylinder is removed.
. Check the pushrod clearance before installing the
master cylinder. and adjust it if necessary (see
page 19-16).. Use a new rod seal on reassemblY. Coat the inner bore lip and outer circumference
of the new rod seal {A) with the recommended
seal grease in the master cylinder set.
. Installthe rod seal ontothe master cylinder with
its grooved side (B)toward the master cylinder.
. Check the brake pedal height and free play after
installing the master cylinder, and adjust it if
necessary (see page 19-6).
19-15

Conventional Brake Components
Master Cylinder Inspection
NOTE:. Before reassembling, check that al I parts are f ree ofdust and other foreign particles.. Do nottryto disassemblethe mastercylinder
assembly. Replace the master cylinder assembly witha new part if necessary.. Do not allow dirt or foreign matter to contaminate thebrake fluid.
RESERVOIB CAPI unecK Ior otocKageof vent holes.
RESERVOIR
,--l RESERvOIR SEALCheck lor damaoe
RESERVOIR HOSESInspect hoses fordamage, leaks, anddeterioration.
r',,.J\+
v
MASTER CYLINDERCheck for leaks, rust, and damage
and deterioration.
STRAINERRemove accumulatedseotment.
19-16
Brake Booster Pushrod Clearance
Adjustment
SpecialTools Required
Pushrod adjustment gauge 07JAG-SD40100
NOTE: Brake booster pushrod-to-piston clearance mustbe checked and adjustments made, if necessarV, beforeinstalling the master cylinder.
1. Setthespecial tool (A) onthe mastercylinder bodv(B), push in the center shaft (C) until the top of itcontacts the end of the secondary piston {D) byturning the adjusting nut (E).
Without disturbing the center shaft's position,
installthe specialtool (A) backwards on the booster.
Install the master cylinder nuts (B), and tighten
them to the specified torque.
Connecl the booster in line with a vacuum gauge
{C) 0-101 kPa {0'-760 mmHg, 30 in.Hg) to thebooster's engine vacuum supply, and maintain anengine speed that will deliver 66 kPa (500 mmHg,20 in.Hg) vacuum.
15 N m {r.511 tbf.ftl

Gonventional Brake Components
IBrake Booster Test
Functional Test
1. With the engine stopped, press the brake pedal
several times to deplete the vacuum reservoir, thenpress the pedal hard, and hold itfor 15 seconds. lfthe pedal sinks, either the master cylinder is
bypassing internally, or the brake system (master
cylinder, lines. modulator, or calipers) is leaking.
2. Start the engine with the brake pedal pressed. lf thepedal sinks slightly, the vacuum booster is workingproperly. lf the pedal height does not vary, thebooster or check valve is faulty.
3. With the engine running, press the brake pedal
lightly. lfthe brake pedal sinks more than 1O mm
{3/8 in, ) in 3 minutes, the master cylinder is faulty.A slight change in pedal height when the Ay'C
compressor cycles on and off is normal. (The A,/C
compressor load changes the vacuum available tothe booster.)
Leak Test
1. Press the brake pedal with the engine running, thenstop the engine. lf the pedal height does not vary
while pressed for 30 seconds, the vacuum boosteris OK. lf the pedal rises, the booster is faulty.
2. With the engine stopped, press the brake pedal
several times using normal pressure. When thepedal is first pressed, it should oe row.
On consecutive applications, the pedal height
should gradually rise. lfthe pedal position does notvarv, check the booster check valve.
19-18
3. Disconnect the brake booster vacuum hose (check
valve built-in) (A) at the booster side.
5.
4.Start the engine, and let it idle. There should bevacuum available. lf no vacuum is available, thecheck valve is not working properly. Repiace thebrake booster vacuum hose and check valve, andrelesI.
Reconnect the brake booster vacuum nose.
Start the engine, and then pinch the brake boostervacuum hose between the check valve and thebooster,
Turn the ignition switch OFF, and wait 30 seconds,Press the brake pedal several times using normalpressu re,
When the pedal is first pressed, it should be low.On consecutive applications, the pedal height
should gradually rise.
. lf the pedal position does notvary, replacethe
brake booster.. lf the pedal position varies, replace the brake
booster vacuum hose/check valve assembly.

Brake Booster Replacement
1.Remove the master cylinder (see page 19-15).
Remove the master cylinder brake lines {A) from
the brake line clip.
c
6x1.0mm9.8 N.m(1.0 kgf.m,7.2 tbf.ft)
Remove the vacuum hose mounting bracket (B).
Disconnect the vacuum hose {C) from the brake
booster.
'-/
.,.,....
alu
i '..
5. Remove the clip (A) and the joint pin (B). and
disconnectthe yoke from the brake pedal.
7.
{'l.3 kgf.m,9 lbf.ftl
Remove the brake booster mounting nuts (C).
Remove the brake booster (A)from the engine
comparlmenr.
INdAdEI. Be careful not to damage the booster
surfaces and threads of the booster stud
bolts.. Be careful not to bend or damage the
brake lines.
lnstallthe brake booster in the reverse order of
removal, and note these items:
. Adjust the pushrod clearance before installing
the brake booster (see page 19-16).. Use a new clip whenever installing.. After installing the brake booster and master
cylinder, fill the reservoir with new brake fluid,
bleed the brake system (see page 19-8), and
adjust the brake pedal height and free play (see
page 19-6),
19-19

Conventional Brake Components
{Brake Hoses and Lines Inspection
1. Inspect the brake hosesfordamage, deterioration, leaks, interference, andtwisting.
2. Check the brake lines for damage, rusting. and leakage. Also check for bent brake lines.
3. Check for leaks at hose and line joints or connections, and retighten if necessary.
4. Check the master cylinder and ABS modulator unit for damage and leakage.
NOTE: Replace the brake hose clip whenever the brake hose is serviced.
15 N.m (1.5 kgf.m, 11 lbf.ftl
ABS MODULATOR UNIT-Io-BRAKE LINE15 N.m {1.5 kgf m.11 lbf.ftl
BRAKE HOSE-to-CALIPERlBANJO BOLTI3il N.m {3.5 kgf.m.25 lbt'ft)BLEEO SCREW9 N.m {0.9 kgf.m,7 lbf.ftl
MASTER CYLINDEB-to-BRAKE LINE15 N m {1.5 kgt.m, ll lbf.ft)
CONTROL VALVE-to-
L
BRAKE HOSE.tO-CALIPER{BANJO BOLTI34 N.m {3.5 kgf.m, 25 lbl.ft)BLEED SCBEW9 N.m10.9 kgf.m, 7 lbf ft)
BRAKE LINE15 N.m 11.5 kgf m, 11 lbf.ft)
BRAKE LINE-Io-BRAKE HOSE15 N.m (1.5 kgf.m,11lbf.ftl
BRAKE LINE-to-BRAKE HOSE
t''/,i'i'
,/ ,l
t t,.. -)
19-24

General Troubleshooting Information
ABS Indicator
. lf the system is OK,theABS indicator goes off 2
seconds after turning the ignition switch ON (ll)
without starting the engine, and then comes on again
and goes off 2 seconds later after starting the engine.
This occurs because the ABS control unitisturned
on by the lG2 power source.. The ABS indicator comes on when the ABS control
unit detects a problem in the system. However, even
though the system is operating properly, the indicator
will come on under these conditions:- Only the drive wheels rotate- One drive wheel is stuck- The vehicle goes into a spin- The ABS continues to operate for a long time.- The vehicle is subjected to an electrical signal
disturbance
To determine the actual cause of the problem, question
the customer about the problem. taking the above
condilions into consideration.
. When a Droblem is detected and lhe ABS indicator
comes on, there are cases when the indicator stays
on until the ignition switch is turned OFF, and cases
when the indicator goes off automatically when the
sYstem returns to normal.- DTC 61: The ABS indicator goes off automatically
when the system returns to normal.- DTC 11, 13,15,17 ,31,32,33, 34, 35, 36, 37, 38, 54,
or 81: The ABS indicator stays on until the ignition
switch is turned OFF whether or not the system
returns to normal.- DfC 12, 14, 16, 1a,21,51,52, or 53; The ABS
indicator goes off when the vehicle is driven again
and the system is OK after the ignition switch is
turned from OFF to ON {ll}.
Diagnostic Trouble Code {DTCI
. The memory can hold three DTCS. However, when
the same DTC is detected more than once, the more
recent DTC is written over the earlier one.
Therefore, when the same problem is detected
repeatedly, it is memorized as a single DTC.. The DTCs are in the order they occurred, beginning
with the most recent.. The DTCS are memorized in the EEPROM (non-
volatile memory). Therefore. the memorized DTCs
are not cleared when the battery is disconnected, the
ignition switch is turned off, or the system returns to
normal. Do the specified procedures to clear the
DTCs.
Self-diagnosis
. Self-diagnosis can be classified into two categories:- Initial diagnosis:
Done right after the engine starts and until the ABS
indicator goes off- Regular diagnosis:
Done rightafterthe initial diagnosis until the
ignition switch is turned OFF. When a problem is detected by self-diagnosis, the
system does the following:- Turns the ABS indicator on- Memorizes the DTC- Stops ABS control
Kickback
The pump motor operates when the ABS is functioning,
and the fluid in the reservoir is forced out to the master
cylinder, causing kickback at the brake pedal.
Pump Motor
. The pump motor operates when the ABS is
functioning.. The ABS control unit checks the pump motor
operation when the vehicle is started the first time
after the ignition switch is turned ON (ll). You may
hear the motor operate at this time, but it is normal.
(cont'd)
19-31