2003 HONDA CIVIC Master cylinder

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

5. With a feeler gauge (A), measure the clearance
between the gauge body and the adjusting nut (B)
as snown,
lf the clearance between the gauge body and the
adjusting nut is 0.4 mm (0.02 in.), the pushrod-to-
piston clearance is 0 mm. However. if the clearance
between the gauge body and the adjusting nut is
0 mm, the pushrod-to-piston clearance is 0 4 mm
{0.02 in.) or more. Therefore it must be adjusted
and rechecked.
Clearance: 0-0./t mm (0-0.02 in.)
lf the clearance is incorrect, loosen the star locknut
(A). and turn the adjuster (B) in or out to adjust.
. Adjust the clearance while the specified vacuum
is appiied to the booster.. Hold the clevis (C) while adjusting.
A0 0.4 mm l0 -0.02 in.) 22N.n
07JAG-SO40100
7. Tighten the star locknut securely.
8. Remove the special tool (D).
9. Check the pushrod length (A) asshownifthe
booster is removed, lf the length is incorrect,
loosen the pushrod locknut (B), and turn the clevis
(C) in or out to adjust.
A116 mm {4.6 in.)
10. Installthe master cylinder (see page l9-15)
10 x 1.0 mm1.5 N'm11.5 kgf.m,11 lbf.ftl
19-17

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

ABS Components
System Description (cont'd)
ABS Modulator
The ABS modulator consists of the inlet solenoid valves, outlet solenoid valves, reservoir, pump, pump motor, and the
damping chamber. The modulator reduces the caliper fluid pressure directly. lt is a circulating-type modulator
becausethe brakefluidcirculatesthroughthecaliper,reservoir,andthemastercylinder.Thehydrauliccontrol has
three modes: pressure intensifying, pressure retaining, and pressure reducing. The hydraulic circuit is an independent
four-channeltype, one channel for each wheel.
Pressure intensifying mode: Inletvalve open, outlel valve closed
Master cylinder fluid is pumped out to the caliper.
Pressure retaining mode: lnlet valve closed, outlet valve closed
Caliper fluid is retained by the inlet valve and outlet valve.
Pressure reducing mode: Inlet valve closed, outlet valve open
Caliper fluid flows through the outlet valve to the reservoir.
lvlotor operation mode: When starting the pressure reducing mode, the pump motor is ON.
When stopping ABS operation, the pump motor is OFF.
The caliper fluid is pumped out by the pump, through the damping chamber, to the
master cvlinder.
19-40