2004 CHRYSLER VOYAGER engine

The power brake booster can be identified by the
tag attached to the body of the booster (Fig. 57). This
tag contains the production part number, the date it
was built, and who the manufacturer of the power
brake booster is.
NOTE: The power brake booster assembly is not a
repairable component and must be replaced as a
complete assembly if found to be faulty in any way.
The check valve located on the power brake
booster face is not repairable, but it can be
replaced separately from the power brake booster.
The different engine combinations used in this
vehicle require different vacuum hose routings to the
power brake booster. All vacuum hoses must be
routed from the engine to the power brake booster
without kinks or excessively tight bends.
OPERATION
The power brake booster reduces the amount of
force required by the driver to obtain the necessary
hydraulic pressure to stop a vehicle.
The power brake booster is vacuum operated. The
vacuum is supplied from the intake manifold on the
engine through a vacuum hose and the power brake
booster check valve (Fig. 56).As the brake pedal is depressed, the power brake
booster's input rod moves forward (Fig. 56). This
opens and closes valves in the power booster allowing
atmospheric pressure to enter on one side of a dia-
phragm. Engine vacuum is always present on the
other side. This difference in pressure forces the out-
put rod of the power brake booster out against the
primary piston of the master cylinder. As the pistons
in the master cylinder move forward this creates the
hydraulic pressure in the brake system.
DIAGNOSIS AND TESTING - POWER BRAKE
BOOSTER
BASIC TEST
(1) With engine off, depress and release the brake
pedal several times to purge all vacuum from the
power brake booster.
(2) Depress and hold the pedal with light effort (15
to 25 lbs. pressure), then start the engine.
The pedal should fall slightly, then hold. Less effort
should be needed to apply the pedal at this time. If
the pedal fell as indicated, perform the VACUUM
LEAK TEST listed after the BASIC TEST. If the
pedal did not fall, continue on with this BASIC
TEST.
(3) Disconnect the vacuum hose on the vacuum
check valve, then place a vacuum gauge in line
between the vacuum hose and the valve.
(4) Start the engine.
(5) When the engine is at warm operating temper-
ature, allow it to idle and check the vacuum at the
gauge.
Fig. 56 Power Brake Booster (Typical)
1 - VACUUM CHECK VALVE
2 - POWER BRAKE BOOSTER ASSEMBLY
3 - INPUT ROD
4 - POWER BOOSTER ASSEMBLY TO DASH PANEL MOUNTING
STUDS (4)
5 - MASTER CYLINDER MOUNTING STUDS (2)
6 - OUTPUT ROD
Fig. 57 MASTER CYLINDER AND BOOSTER
1 - POWER BRAKE BOOSTER
2 - BOOSTER IDENTIFICATION LABEL
3 - FLUID LEVEL SWITCH CONNECTOR
4 - PRIMARY BRAKE TUBE NUT
5 - SECONDARY BRAKE TUBE NUT
6 - MASTER CYLINDER
RSBRAKES - BASE5-41
POWER BRAKE BOOSTER (Continued)

If the vacuum supply is 12 inches Hg (40.5 kPa) or
more, the power brake booster is defective and must
be replaced. If the vacuum supply is below 12 inches
Hg, continue on with this BASIC TEST.
(6) Shut off the engine.
(7) Connect the vacuum gauge to the vacuum ref-
erence port on the engine intake manifold.
(8) Start the engine and observe the vacuum
gauge.
If the vacuum is still low, check the engine tune
and repair as necessary. If the vacuum is above 12
inches Hg, the hose or check valve to the booster has
a restriction or leak.
Once an adequate vacuum supply is obtained,
repeat the BASIC TEST.
VACUUM LEAK TEST
(1) Disconnect the vacuum hose on the vacuum
check valve, then place a vacuum gauge in line
between the vacuum hose and the valve.
(2) Start the engine.
(3) Allow the engine to warm up to normal operat-
ing temperature and engine idle.
(4) Using vacuum line pliers, close off the vacuum
supply hose near the booster, but before the vacuum
gauge, then observe the vacuum gauge.
If the vacuum drop exceeds 1.0 inch Hg (3.3 kPa)
in one minute, repeat the above steps to confirm the
reading. The vacuum loss should be less than 1.0
inch Hg in one minute time span. If the loss is more
than 1.0 inch Hg, replace the power brake booster. If
it is not, continue on with this test.
(5) Remove the pliers from the hose temporarily.
(6) Apply light effort (approximately 15 lbs. of
force) to the brake pedal and hold the pedal steady.
Do not move the pedal once the pressure is applied
or the test results may vary.
(7) Have an assistant reattach the vacuum line
pliers to the vacuum supply hose.
(8) Allow 5 seconds for stabilization, then observe
the vacuum gauge.
If the vacuum drop exceeds 3.0 inches Hg (10 kPa)
in 15 seconds, repeat the above steps to confirm the
reading. The vacuum loss should be less than 3.0
inches Hg in 15 seconds time span. If the loss is
more than 3.0 inches Hg, replace the power brake
booster. If it is not, the booster is not defective.
(9) Remove the pliers and vacuum gauge.
REMOVAL
REMOVAL - LHD
CAUTION: Reserve vacuum in power brake booster
must be pumped down (removed) before removing
master cylinder from booster. This is necessary toprevent booster from sucking in any contamination
as master cylinder is removed. This can be done
simply by pumping the brake pedal, with the vehi-
cle's engine not running, until a firm feeling brake
pedal is achieved.
(1) With engine not running, pump the brake
pedal until a firm pedal is achieved (4-5 strokes).
(2) Remove negative battery cable terminal from
battery.
(3) Remove positive battery cable terminal from
battery.
(4) Remove battery thermal guard shield.
(5) Remove battery clamp, nut and battery from
the battery tray.
(6) Remove screw securing engine coolant filler
tube to battery tray.
(7) If the vehicle is equipped with speed control,
disconnect the vacuum hose at the vacuum tank built
into the battery tray.
(8) Remove the two nuts and one bolt securing bat-
tery tray in place. Remove battery tray.
(9) If vehicle is equipped with speed control:
(a) Disconnect wiring harness connector from
the speed control servo.
(b) Remove the two servo mounting nuts.
(c) Lay speed control servo off to the side, out of
the way.
(10) Remove the wiper module (unit). (Refer to 8 -
ELECTRICAL/WIPERS/WASHERS/WIPER MOD-
ULE - REMOVAL)
(11) Disconnect wiring harness connector from
brake fluid level switch in master cylinder fluid res-
ervoir (Fig. 58).
Fig. 58 Master Cylinder And Booster
1 - POWER BRAKE BOOSTER
2 - BOOSTER IDENTIFICATION LABEL
3 - FLUID LEVEL SWITCH CONNECTOR
4 - PRIMARY BRAKE TUBE NUT
5 - SECONDARY BRAKE TUBE NUT
6 - MASTER CYLINDER
5 - 42 BRAKES - BASERS
POWER BRAKE BOOSTER (Continued)

CAUTION: Before removing the master cylinder
from the power brake vacuum booster, the master
cylinder and vacuum booster must be thoroughly
cleaned. This must be done to prevent dirt particles
from falling into the power brake vacuum booster.
(12) Clean area where master cylinder assembly
attaches to power brake booster. Use only a solvent
such as MopartBrake Parts Cleaner or equivalent.
(13) Disconnect primary and secondary brake
tubes from ABS integrated control unit or non-ABS
junction block (Fig. 59). Install sealing plugs in the
now open brake tube ports and install caps on ends
of tubes.
NOTE: It is not necessary to remove the brake
tubes from the master cylinder when removing the
master cylinder from the vacuum booster.
(14) Remove two nuts attaching master cylinder to
power brake booster (Fig. 59).
(15) Slide master cylinder straight out of power
brake booster. Remove master cylinder with primary
and secondary tubes from vehicle.
CAUTION: A seal on the rear of the master cylinder
is used to create the seal for holding vacuum in the
power brake vacuum booster. The vacuum seal on
the master cylinder MUST be replaced whenever the
master cylinder is removed from the power brake
vacuum booster.
(16) Disconnect vacuum hose from check valve
located on vacuum booster.DO NOT REMOVE
CHECK VALVE FROM POWER BRAKE
BOOSTER.(17) Inside vehicle, remove silencer panel under
instrument panel below steering column.
(18) Locate the booster input rod to brake pedal
connection under the instrument panel. Position a
small screwdriver between the center tang on the
power brake booster input rod to brake pedal pin
retaining clip (Fig. 60).
(19) Rotate screwdriver enough to allow retaining
clip center tang to pass over end of brake pedal pin.
Then pull retaining clip off brake pedal pin.Discard
retaining clip. It is not to be reused. Replace
only with a new retaining clip when assem-
bling.
(20) Slide booster input rod off pedal pin.
(21) Remove the four nuts attaching power brake
booster to dash panel (Fig. 61).
(22) Slide power brake booster forward and remove
through engine compartment (Fig. 62).
CAUTION: Do not attempt to disassemble the power
brake vacuum booster. It is serviced ONLY as a
complete assembly.
REMOVAL - RHD
CAUTION: Reserve vacuum in power brake booster
must be pumped down (removed) before removing
master cylinder from booster. This is necessary to
prevent booster from sucking in any contamination
as master cylinder is removed. This can be done
simply by pumping the brake pedal, with the vehi-
cle's engine not running, until a firm feeling brake
pedal is achieved.
Fig. 59 Master Cylinder Mounting
1 - MASTER CYLINDER MOUNTING NUTS
2 - MASTER CYLINDER
3 - SECONDARY TUBE NUT AT ICU
4 - PRIMARY TUBE NUT AT ICU
Fig. 60 Vacuum Booster Input Rod Retaining Pin
1 - BRAKE PEDAL
2 - INPUT ROD
3 - SCREWDRIVER
4 - RETAINING CLIP
5 - BRAKE PEDAL PIN
RSBRAKES - BASE5-43
POWER BRAKE BOOSTER (Continued)

(1) With engine not running, pump the brake
pedal until a firm pedal is achieved (4 or 5 strokes).
(2) Remove negative battery cable terminal from
battery.
(3) Remove positive battery cable terminal from
battery.
(4) Remove battery thermal guard shield.
(5) Remove battery clamp, nut and battery from
the battery tray.
(6) If the vehicle is equipped with speed control,
disconnect the vacuum hose at the vacuum tank built
into the battery tray.
(7) Remove the two nuts and one bolt securing bat-
tery tray in place. Remove battery tray.
(8) If vehicle is equipped with speed control:
(a) Disconnect wiring harness connector from
the speed control servo.
(b) Remove the two servo mounting nuts.(c) Lay speed control servo off to the side, out of
the way.
(9) If the vehicle is equipped with the 2.5L diesel
engine, remove the coolant recovery pressure con-
tainer and bracket. (Refer to 7 - COOLING/ENGINE/
COOLANT RECOVERY PRESS CONTAINER -
REMOVAL)
(10) Disconnect wiring harness connector from
brake fluid level switch in master cylinder fluid res-
ervoir (Fig. 63).
CAUTION: Before removing the master cylinder
from the power brake vacuum booster, the master
cylinder and vacuum booster must be thoroughly
cleaned. This must be done to prevent dirt particles
from falling into the power brake vacuum booster.
(11) Clean area where master cylinder assembly
attaches to power brake booster. Use only a solvent
such as MopartBrake Parts Cleaner or equivalent.
NOTE: It is not necessary to remove the brake
tubes from the master cylinder when removing the
master cylinder from the booster.
(12) Remove two nuts attaching master cylinder to
power brake booster (Fig. 64).
(13) Slide master cylinder straight out of power
brake booster. Lay master cylinder with primary and
secondary tubes to the side, out of the way.
Fig. 61 Booster Mounting
1 - DASH BRACKET
2 - POWER BRAKE BOOSTER
3 - BRAKE PEDAL ASSEMBLY
Fig. 62 Booster Removal/Installation
Fig. 63 RHD Master Cylinder And Power Brake
Booster
1 - POWER BRAKE BOOSTER
2 - BRAKE FLUID LEVEL SWITCH
3 - FLUID RESERVOIR
4 - MASTER CYLINDER
5 - 44 BRAKES - BASERS
POWER BRAKE BOOSTER (Continued)

CAUTION: A seal on the rear of the master cylinder
is used to create the seal for holding vacuum in the
power brake vacuum booster. The vacuum seal on
the master cylinder MUST be replaced whenever the
master cylinder is removed from the power brake
vacuum booster.
(14) Disconnect vacuum hose from check valve
located on booster.DO NOT REMOVE CHECK
VALVE FROM POWER BRAKE BOOSTER.
(15) Under the instrument panel, remove booster
input rod trim cover.
(16) Locate the booster input rod to brake pedal
torque shaft connection under the instrument panel.
Position a small screwdriver between the center tang
on the retaining clip (Fig. 65).
(17) Rotate screwdriver enough to allow retaining
clip center tang to pass over end of brake pedal pin.
Then pull retaining clip off brake pedal torque shaft
pin.Discard retaining clip. It is not to be
reused. Replace only with a new retaining clip
when assembling.
(18) Remove booster input rod from pedal torque
shaft pin.
(19) Remove the three easily accessed mounting
nuts attaching power brake booster to dash panel
and loosen fourth (Fig. 66). As fourth nut is loosened,
push the booster forward periodically until the nut
can be completely removed.
(20) Slide power brake booster forward and remove
through engine compartment (Fig. 67).
CAUTION: Do not attempt to disassemble the power
brake vacuum booster. It is serviced ONLY as a
complete assembly.
Fig. 64 RHD Master Cylinder Mounting
1 - PRIMARY BRAKE TUBE NUT
2 - SECONDARY BRAKE TUBE NUT
3 - MASTER CYLINDER MOUNTING NUTS
Fig. 65 Booster Input Rod Pin Retaining Clip
(Typical)
1 - BRAKE PEDAL
2 - INPUT ROD
3 - SCREWDRIVER
4 - RETAINING CLIP
5 - BRAKE PEDAL PIN
Fig. 66 Booster, Torque Shaft And Pedal Mounting
1 - PEDAL MOUNTING NUT
2 - BRAKE PEDAL ASSEMBLY
3 - PEDAL MOUNTING NUT
4 - PEDAL TORQUE SHAFT
5 - BOOSTER MOUNTING NUT
6 - BOOSTER BRACKET
7 - POWER BRAKE BOOSTER
8 - BOOSTER BRACKET MOUNTING NUT
RSBRAKES - BASE5-45
POWER BRAKE BOOSTER (Continued)

the mounting nuts to a torque of 14 N´m (124 in.
lbs.).
(16) Install the battery tray. Install the two nuts
and one bolt attaching the battery tray to the vehicle.
Tighten the bolt and nuts to a torque of 14 N´m (124
in. lbs.).
(17) If vehicle is equipped with speed control, con-
nect the servo vacuum hose to the vacuum tank on
the battery tray.
(18) Install the air inlet resonator and hoses as an
assembly on the throttle body and air cleaner hous-
ing. Securely tighten hose clamp at air cleaner hous-
ing and throttle body.
(19) Secure the engine coolant filler neck to the
battery tray with its mounting screw.
(20) Install the battery, clamp and mounting nut.
(21) Install the positive battery cable on the bat-
tery.
(22) Install the negative battery cable on the bat-
tery.
(23) Install the battery thermal guard shield.
(24) Bleed the base brakes as necessary. (Refer to
5 - BRAKES - STANDARD PROCEDURE)
(25) Road test vehicle to ensure operation of the
brakes.
INSTALLATION - RHD
(1) Position power brake booster on dash panel
using the reverse procedure of its removal (Fig. 67).
(2) Below instrument panel, first install the two
upper nuts mounting the booster to the dash panel,
drawing it into place, then install the two lower
mounting nuts. Tighten the mounting nuts to a
torque of 29 N´m (250 in. lbs.).
(3) Using lubriplate, or equivalent, coat the sur-
face of the brake pedal torque shaft pin where it con-
tacts the booster input rod.CAUTION: When installing the brake pedal torque
shaft pin on the power brake booster input rod, do
not re-use the old retaining clip.
(4) Install booster input rod on brake pedal torque
shaft pin and install a NEW retaining clip (Fig. 70).
(5) Install booster input rod trim cover.
(6) Connect vacuum hose to check valve on power
brake booster.
CAUTION: The master cylinder (and its rear seal) is
used to create the seal for holding vacuum in the
vacuum booster. The vacuum seal on the master
cylinder MUST be replaced with a NEW seal when-
ever the master cylinder is removed from the vac-
uum booster.
CAUTION: When removing the vacuum seal from
the master cylinder, do not use a sharp tool.
(7) Using a soft tool such as a trim stick, remove
the vacuum seal from the master cylinder mounting
flange.
(8) Install a NEW vacuum seal on rear mounting
flange of the master cylinder (Fig. 71).
(9) Position master cylinder on studs of booster,
aligning push rod on booster with master cylinder
piston.
(10) Install the two nuts mounting the master cyl-
inder to the booster (Fig. 64). Tighten both mounting
nuts to a torque of 25 N´m (225 in. lbs.).
(11) Connect wiring harness connector to brake
fluid level switch in the master cylinder fluid reser-
voir (Fig. 63).
Fig. 69 Vacuum Seal (Typical)
1 - MASTER CYLINDER ASSEMBLY
2 - VACUUM SEAL
Fig. 70 Retaining Pin Installed On Brake Pedal Pin
(Typical)
1 - BRAKE PEDAL
2 - RETAINING CLIP
3 - BOOSTER INPUT ROD
RSBRAKES - BASE5-47
POWER BRAKE BOOSTER (Continued)

(12) If the vehicle is equipped with the 2.5L diesel
engine, install the coolant recovery pressure con-
tainer and bracket. (Refer to 7 - COOLING/ENGINE/
COOLANT RECOVERY PRESS CONTAINER -
INSTALLATION)
(13) If equipped with speed control, install speed
control servo and connect wiring connector. Tighten
the mounting nuts to a torque of 14 N´m (124 in.
lbs.).
(14) Install the battery tray. Install the two nuts
and one bolt attaching the battery tray to the vehicle.
Tighten the bolt and nuts to a torque of 14 N´m (124
in. lbs.).
(15) If vehicle is equipped with speed control, con-
nect the servo vacuum hose to the vacuum tank on
the battery tray.
(16) Install the battery, clamp and mounting nut.
(17) Install the positive battery cable on the bat-
tery.
(18) Install the negative battery cable on the bat-
tery.
(19) Install the battery thermal guard shield.
CAUTION: Do not reuse the original brake lamp
switch. The switch can only be adjusted once. That
is during initial installation of the switch. If the
switch is not adjusted properly or has been
removed for some service, a new switch must be
installed and adjusted.
(20) Remove and replace the brake lamp switch
with a NEW switch. (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - EXTERIOR/BRAKE LAMP
SWITCH - REMOVAL), (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - EXTERIOR/BRAKE LAMP
SWITCH - INSTALLATION)(21) Bleed the base brakes as necessary. (Refer to
5 - BRAKES - STANDARD PROCEDURE)
(22) Road test vehicle to ensure proper operation
of the brakes.
PROPORTIONING VALVE
DESCRIPTION - PROPORTIONING VALVE
(HEIGHT SENSING)
NOTE: Only vehicles without antilock brakes (ABS)
have a proportioning valve. Vehicles with ABS uti-
lize electronic brake distribution which is controlled
through the ABS integrated control unit.
Vehicles not equipped with ABS use a height sens-
ing proportioning valve. It is mounted to the body of
the vehicle above the rear axle (Fig. 72). It has an
actuator lever that attaches to the rear axle and
moves with the axle to help the valve sense the vehi-
cle height.
CAUTION: The height sensing proportioning valve
is not adjustable. No attempt should be made to
adjust it. It is replaced as a complete assembly.
CAUTION: The use of after-market load leveling or
load capacity increasing devices on this vehicle are
prohibited. Using air shock absorbers or helper
springs on this vehicle will cause the height sens-
ing proportioning valve to inappropriately reduce
the hydraulic pressure to the rear brakes. This inap-
propriate reduction in hydraulic pressure potentially
could result in increased stopping distance of the
vehicle.
OPERATION - PROPORTIONING VALVE
(HEIGHT SENSING)
Vehicles not equipped with ABS use a height sens-
ing proportioning valve.
The height sensing proportioning valve operates
similarly to a standard proportioning valve in the fol-
lowing way. As hydraulic pressure is applied to the
valve, full input hydraulic pressure is supplied to the
rear brakes up to a certain pressure point, called the
split point. Beyond the split point, the proportioning
valve reduces the amount of hydraulic pressure to
the rear brakes according to a given ratio. Thus, on
light brake applications, approximately equal
hydraulic pressure will be transmitted to both the
front and rear brakes. Upon heavier brake applica-
tions, the hydraulic pressure transmitted to the rear
brakes will be lower than the front brakes. This will
prevent premature rear wheel lockup and skid.
Fig. 71 Vacuum Seal (Typical)
1 - MASTER CYLINDER ASSEMBLY
2 - VACUUM SEAL
5 - 48 BRAKES - BASERS
POWER BRAKE BOOSTER (Continued)

(Fig. 12). The ICU is located below the master cylin-
der in the engine compartment (Fig. 13).
Two different ICU's (HCU and CAB) are used on
this vehicle depending on whether or not the vehicle
is equipped with traction control. The HCU on a
vehicle equipped with traction control has a valve
block that is approximately one inch longer than a
HCU on a vehicle that is equipped with ABS only.
The ABS-only ICU consists of the following compo-
nents: the CAB, eight (build/decay) solenoid valves
(four inlet valves and four outlet valves), valve block,
fluid accumulators, a pump, and an electric motor.
The ABS-with traction control ICU consists of the
following components: the CAB, eight (build/decay)solenoid valves (four inlet valves and four outlet
valves), two traction control (ASR) valves, two
hydraulic shuttle valves, valve block, fluid accumula-
tors, a pump, and an electric motor.
The replaceable components of the ICU are the
HCU and the CAB. No attempt should be made to
service any individual components of the HCU or
CAB. For information on the CAB, (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/CONTROLLER ANTILOCK BRAKE -
DESCRIPTION).
OPERATION
For information of the ICU, refer to these individ-
ual components of the ICU:
²CONTROLLER ANTILOCK BRAKE (CAB)
(Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/CONTROLLER ANTILOCK
BRAKE - OPERATION)
²HYDRAULIC CONTROL UNIT (HCU) (Refer to
5 - BRAKES - ABS/HYDRAULIC/MECHANICAL/
HCU (HYDRAULIC CONTROL UNIT) - OPERA-
TION)
For information on the ICU's hydraulic circuits,
refer to HYDRAULIC CIRCUITS AND VALVE
OPERATION. (Refer to 5 - BRAKES - ABS/HY-
DRAULIC/MECHANICAL - OPERATION)
REMOVAL
REMOVAL - LHD
(1) Disconnect the negative (ground) cable from
the battery and isolate cable.
(2) Remove the battery shield.
(3) Remove the battery (Refer to 8 - ELECTRI-
CAL/BATTERY SYSTEM/BATTERY - REMOVAL).
(4) Disconnect the vacuum hose connector at the
tank built into the battery tray.
(5) Remove the screw securing the engine coolant
filler neck to the battery tray.
(6) Remove the battery tray (Refer to 8 - ELEC-
TRICAL/BATTERY SYSTEM/TRAY - REMOVAL).
(7) Using a brake pedal depressor, move and lock
the brake pedal to a position past the first inch of
pedal travel.This will prevent brake fluid from
draining out of the master cylinder once the
brake tubes are removed from the HCU.
CAUTION: Do not apply a 12±volt power source to
any terminals of the 24-way CAB connector when
disconnected.
(8) Disconnect the wiring harness connector from
the speed control servo.
(9) Remove the speed control servo mounting nuts
and move the servo out of the way.
Fig. 12 INTEGRATED CONTROL UNIT (ICU)
1 - PUMP/MOTOR
2 - HCU
3 - PUMP/MOTOR CONNECTOR
4 - CAB
Fig. 13 ICU LOCATION IN VEHICLE
1 - POWER BRAKE BOOSTER
2 - MASTER CYLINDER
3 - ICU
5 - 90 BRAKES - ABSRS
ICU (INTEGRATED CONTROL UNIT) (Continued)