Chrysler Town, Dodge Caravan. Manual - part 47

(2) Remove brake fluid reservoir cap. Using a

syringe or equivalent type tool empty as much brake
fluid as possible from the reservoir.

CAUTION: When removing fluid reservoir from the
master cylinder, do not pry off using any type of
tool. This can damage the fluid reservoir or master
cylinder housing.

(3) Remove the master cylinder assembly from the

power brake vacuum booster. (Refer to 5 - BRAKES -
BASE/HYDRAULIC/MECHANICAL/MASTER

CYL-

INDER - REMOVAL).

(4) Mount the master cylinder in a vise using the

master cylinder mounting flange.

(5) Using correct size pin punch, remove the two

retaining pins between the fluid reservoir and master
cylinder housing (Fig. 52).

(6) Rock the brake fluid reservoir from side to side

while pulling up to remove it from the seal grommets
in master cylinder housing.

(7) Remove the two master cylinder housing to

brake fluid reservoir seal grommets (Fig. 53).

ASSEMBLY - MASTER CYLINDER (FLUID
RESERVOIR)

(1) Install new master cylinder housing to brake

fluid reservoir sealing grommets in master cylinder
housing (Fig. 53).

(2) Lubricate reservoir mounting area with fresh

clean brake fluid. Place reservoir in position over
sealing grommets. Seat reservoir into sealing grom-
mets using a rocking motion while firmly pressing
down on fluid reservoir.

(3) Be sure fluid reservoir is positioned properly on

master cylinder. Bottom of fluid reservoir is to be

touching the top of both sealing grommets
when properly installed on master cylinder
housing.

(4) Install the two fluid reservoir to master cylin-

der retaining pins (Fig. 52).

(5) Install the master cylinder assembly on the

power brake booster. (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/MASTER

CYLINDER

INSTALLATION)

(6) Fill fluid reservoir to its proper level as indi-

cated on the side of the fluid reservoir.

INSTALLATION

INSTALLATION - LHD

CAUTION: Different types of master cylinders are
used on this vehicle depending on brake options. If
a new master cylinder is being installed, be sure it
is the correct master cylinder for the type of brake
system the vehicle is equipped with.

CAUTION: When replacing the master cylinder on a
vehicle, a NEW vacuum seal MUST be installed on
the master cylinder.

(1) Install a NEW vacuum seal on master cylinder

making sure seal fits squarely in groove of master
cylinder casting.

(2) Position master cylinder on studs of power

brake booster, aligning booster push rod with master
cylinder piston.

(3) Install the two master cylinder mounting nuts

(Fig. 50). Tighten both mounting nuts to a torque of
25 N·m (225 in. lbs.).

Fig. 52 Fluid Reservoir Retaining Pins (Typical)

1 - FLUID RESERVOIR
2 - RETAINING PINS
3 - MASTER CYLINDER

Fig. 53 Master Cylinder To Fluid Reservoir Seal

Grommets

1 - SEAL GROMMETS
2 - MASTER CYLINDER

5 - 38

BRAKES - BASE

MASTER CYLINDER (Continued)

CAUTION: When tightening the primary and sec-
ondary brake tube nuts at master cylinder, be sure
brake tubes do not contact any other components
within the vehicle and that there is slack in the flex-
ible sections of the tubes. This is required due to
the movement between the ABS ICU and the master
cylinder while the vehicle is in motion.

(4) Connect primary and secondary brake tubes to

master cylinder primary and secondary ports (Fig.
49). Brake tubes must be held securely when tight-
ened to control orientation of flex section. Tighten
tube nuts to a torque of 17 N·m (145 in. lbs.).

(5) Install wiring harness connector to brake fluid

level switch mounted in brake fluid reservoir (Fig.
49).

(6) Install battery, clamp and nut.
(7) Install battery shield.
(8) Connect positive battery terminal.
(9) Connect negative battery terminal.
(10) Fill master cylinder with clean, fresh Mopar

Brake Fluid or equivalent.

(11) Road test vehicle to ensure proper operation of

brakes.

INSTALLATION - RHD

CAUTION: When replacing the master cylinder on a
vehicle, a NEW vacuum seal MUST be installed on
the master cylinder.

(1) Install a NEW vacuum seal on master cylinder

making sure seal fits squarely in groove of master
cylinder casting.

(2) Position master cylinder on studs of power

brake booster, aligning booster push rod with master
cylinder piston.

(3) Install the two master cylinder mounting nuts

(Fig. 51). Tighten both mounting nuts to a torque of
25 N·m (225 in. lbs.).

(4) Connect primary and secondary brake tubes to

master cylinder primary and secondary ports (Fig.
51). Brake tubes must be held securely when tight-
ened to control orientation of flex section. Tighten
tube nuts to a torque of 17 N·m (145 in. lbs.).

(5) Install wiring harness connector to brake fluid

level switch mounted in brake fluid reservoir (Fig.
47).

(6) Install battery, clamp and nut.
(7) Install battery shield.
(8) Connect positive battery terminal.
(9) Connect negative battery terminal.
(10) Fill master cylinder with clean, fresh Mopar

Brake Fluid or equivalent.

(11) Road test vehicle to ensure proper operation of

brakes.

PEDAL TORQUE SHAFT - RHD

REMOVAL

(1) Remove the instrument panel. (Refer to 23 -

BODY/INSTRUMENT

PANEL/INSTRUMENT

PANEL ASSEMBLY - REMOVAL)

(2) Remove the HVAC housing. (Refer to 24 -

HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - REMOVAL)

(3) Remove the retaining clip at the torque shaft

end of the brake pedal-to-torque shaft link. Remove
the link from the torque shaft. Discard the retaining
clip. It is not to be reused. Replace with a new clip
when reassembled.

(4) Locate the booster input rod-to-brake pedal

torque shaft connection and remove the retaining clip
(Fig. 54). Discard the retaining clip. It is not to be
reused. Replace with a new clip when reassembled.

(5) Remove the four (4) brake booster retaining

nuts from inside the passenger compartment (Fig.
55).

(6) Remove the retaining nut from the brake

booster bracket located above the booster in the
engine compartment (Fig. 55).

(7) Remove the power brake booster bracket.
(8) Rotate the pedal torque shaft and remove it out

the left side of the vehicle.

INSTALLATION

(1) Lubricate both ends of the torque shaft with

MS-4517 Lubricant or equivalent and install the
torque shaft from the left side reversing the removal
procedure.

(2) Install the brake booster bracket on the left

end of the shaft.

(3) Install the retaining nut for the brake booster

bracket in the engine compartment. Tighten the
mounting nut to a torque of 29 N·m (250 in. lbs.).

BRAKES - BASE

5 - 39

MASTER CYLINDER (Continued)

(4) Install the four brake booster retaining nuts

inside

the

passenger

compartment.

Tighten

the

mounting nuts to a torque of 29 N·m (250 in. lbs.).

(5) Using lubriplate, or equivalent, coat the sur-

face of the brake pedal torque shaft pin where it con-

tacts the booster input rod. Also coat the surface of
the brake pedal torque shaft pin where it contacts
the brake pedal link.

CAUTION: When installing the power brake booster
input rod on the brake pedal torque shaft pin, do
not reuse the old retaining clip.

(6) Install booster input rod on brake pedal torque

shaft pin and install a NEW retaining clip (Fig. 54).

CAUTION: When installing the brake pedal link on
the brake pedal torque shaft pin, do not reuse the
old retaining clip.

(7) Connect the brake pedal link to the torque

shaft. Install a NEW retaining clip at the torque
shaft end of the brake pedal-to-torque shaft link.

(8) Install the HVAC housing. (Refer to 24 - HEAT-

ING & AIR CONDITIONING/DISTRIBUTION/HVAC
HOUSING - INSTALLATION)

(9) Install the instrument panel. (Refer to 23 -

BODY/INSTRUMENT

PANEL/INSTRUMENT

PANEL ASSEMBLY - INSTALLATION)

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

not

adjusted

properly

has

been

removed for some service, a new switch must be
installed and adjusted.

(10) 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)

(11) Road test vehicle to ensure proper operation of

the brakes.

POWER BRAKE BOOSTER

DESCRIPTION

The power brake booster mounts on the engine

compartment side of the dash panel. It is connected
to the brake pedal by the input (push) rod (Fig. 56).
The master cylinder is bolted to the front of the
booster. A vacuum line connects the power brake
booster to the intake manifold.

All vehicles use a 270 mm single diaphragm vac-

uum power brake booster.

Vehicles equipped with Disc/Disc brakes use a dif-

ferent power brake booster than vehicles equipped
with Disc/Drum brakes. Differences between the two
are internal. Service is the same for all boosters.

Fig. 54 POWER BRAKE BOOSTER BRACKET

1 - BOOSTER BRACKET
2 - PEDAL TORQUE SHAFT
3 - RETAINING CLIP
4 - BOOSTER MOUNTING NUTS

Fig. 55 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

5 - 40

BRAKES - BASE

PEDAL TORQUE SHAFT - RHD (Continued)

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

BRAKES - BASE

5 - 41

POWER BRAKE BOOSTER (Continued)

Content .. 45 46 47 48 ..