2000 DODGE NEON vacuum

CAUTION: Discard the used retaining clip, it is not
to be reused. Replace the clip with a new one on
reassembly.
(11) Remove the four nuts attaching the power
brake booster to the instrument panel (Fig. 51). The
nuts are accessible from under the instrument panel
in the area of the brake pedal bracket.
(12) Slide the power brake booster forward until
mounting studs clear the instrument panel. Turn the
booster sideways (Fig. 52), then remove it from the
vehicle.
INSTALLATION
(1) Turn the power brake booster sideways (Fig.
52), then install it into the engine compartment down
past the heater hoses and the strut tower. Rotate the
booster so its four mounting studs and input rod are
pointed straight toward the instrument panel. Slide
the input rod and studs through the instrument
panel and into mounting position.
(2) Under the instrument panel, install the four
power brake booster mounting nuts (Fig. 51). Tighten
the nuts to a torque of 34 N´m (300 in. lbs.).
(3) Using lubriplate, or an equivalent, coat the sur-
face of the brake pedal pin where it contacts the
brake booster input rod.
Fig. 49 Vacuum Check Valve
1 ± VACUUM CHECK VALVE
Fig. 50 Retaining Clip
1 ± BRAKE PEDAL
2 ± INPUT ROD
3 ± SCREWDRIVER
4 ± RETAINING CLIP
5 ± BRAKE PEDAL PIN
Fig. 51 Power Brake Booster Mounting
1 ± POWER BRAKE BOOSTER MOUNTING NUTS
2 ± BRAKE PEDAL
Fig. 52 Booster Removal/Installation
1 ± POWER BRAKE BOOSTER
PLBRAKES 5 - 31
REMOVAL AND INSTALLATION (Continued)

CAUTION: Use only a new brake booster input rod-
to-brake pedal retaining clip to ensure proper
retainment.
(4) Connect the power brake booster input rod-to-
brake pedal pin. Install a new retaining clip. Do not
use the old clip.
(5) Connect all previously removed vacuum hoses
to the vacuum check valve (Fig. 49).
(6) If the vehicle is equipped with ABS, install the
ICU mounting bracket on the frame rail using its
three bolts. Tighten the nuts to a torque of 23 N´m
(200 in. lbs.).
(7) If the vehicle is equipped with ABS, reinstall
the ICU. Refer to INTEGRATED CONTROL UNIT in
REMOVAL AND INSTALLATION within the
ANTILOCK BRAKE SYSTEM section of this service
manual group for the procedure.
(8) Install the master cylinder. For the master cyl-
inder without ABS removal and installation proce-
dure, refer to MASTER CYLINDER in this section of
this service manual group. For the master cylinder
with ABS removal and installation procedure, refer
to MASTER CYLINDER in the ANTILOCK BRAKE
SYSTEM section of this service manual group.
(9) Position the battery tray back in place. Install
the two bolts, then the two nuts mounting the bat-
tery tray to its bracket (Fig. 48). Tighten the two
bolts and nuts to a torque of 34 N´m (25 ft. lbs.).
(10) Reinstall the air cleaner box onto its grom-
meted alignment post (Fig. 48).
(11) Install the one nut and one bolt securing the
air cleaner box in place, then connect the wiring har-
ness connector at the air inlet sensor.
(12) Install the battery and clamp it in place.
(13) Connect the positive, then the negative
(ground) cable on the battery.
(14) Adjust the stop lamp switch as necessary.
Refer to STOP LAMP SWITCH in the ADJUST-
MENTS section of this group.
(15) Bleed the base brake system.
(16) Road test the vehicle to ensure proper opera-
tion of the brakes.
PROPORTIONING VALVE
NOTE: Before proceeding with this procedure,
review SERVICE WARNINGS AND CAUTIONS at the
beginning of REMOVAL AND INSTALLATION in this
section.
REMOVAL
(1) Using a brake pedal holder, depress the brake
pedal past its first one inch of travel and hold it in
this position (Fig. 53). This will isolate the master
cylinder from the brake hydraulic system and willnot allow the brake fluid to drain out of the master
cylinder reservoir.
(2) Disconnect the brake tube from the proportion-
ing valve requiring removal (Fig. 54).
(3) Unscrew the Proportioning valve from the mas-
ter cylinder.
Fig. 53 Brake Pedal Holder
1 ± CLUTCH PEDAL (IF EQUIPPED WITH MANUAL TRANSAXLE)
2 ± THROTTLE PEDAL
3 ± BRAKE PEDAL HOLDING TOOL
4 ± STEERING WHEEL
5 ± DRIVER'S SEAT
6 ± BRAKE PEDAL
Fig. 54 Proportioning Valves On Master Cylinder
1 ± RIGHT FRONT BRAKE TUBE
2 ± LEFT FRONT BRAKE TUBE
3 ± LEFT REAR BRAKE TUBE
4 ± REAR PROPORTIONING VALVES
5 ± RIGHT REAR BRAKE TUBE
5 - 32 BRAKESPL
REMOVAL AND INSTALLATION (Continued)

SPECIFICATIONS
BRAKE FLUID
The brake fluid used in this vehicle must conform
to DOT 3 specifications and SAE J1703 standards.
No other type of brake fluid is recommended or
approved for usage in the vehicle brake system. Use
only Mopar brake fluid or an equivalent from a
tightly sealed container.
CAUTION: Never use reclaimed brake fluid or fluid
from an container which has been left open. An
open container will absorb moisture from the air
and contaminate the fluid.
CAUTION: Never use any type of a petroleum-
based fluid in the brake hydraulic system. Use of
such type fluids will result in seal damage of the
vehicle brake hydraulic system causing a failure of
the vehicle brake system. Petroleum based fluids
would be items such as engine oil, transmission
fluid, power steering fluid, etc.
BRAKE ACTUATION SYSTEM
ACTUATION:
Vacuum Operated Power Brakes.....Standard
Hydraulic System.......Dual-Diagonally Split
BRAKE PEDAL:
Pedal Ratio..........................3.41
POWER BRAKE BOOSTER:
Make/Type..................Bosch/Vacuum
Mounting Studs.................. M8x1.25
Diaphragm Size/Type........ 205mmTandem
MASTER CYLINDER ASSEMBLY:
Type ........................Dual Tandem
Body Material...........Anodized Aluminum
Reservoir Material.............Polypropelene
MASTER CYLINDER BORE STROKE AND
SPLIT:
NonABS ..............22.23 mm x 34.0 mm
(0.875 in. x 1.34 in.)
ABS . . 23.82 mm x 34.0 mm (0.937 in. x 1.34 in.)
Displacement Split.................. 50/50MASTER CYLINDER FLUID OUTLET PORTS:
Tube Fitting Type...... SAE45ÉInverted Flare
W/ABS - Primary Tube Nut
Thread........................7/16 in.±24
W/ABS - Secondary Tube Nut
Thread........................ 3/8in.±24
W/O ABS - All Tube Nut Threads....7/16 in.±24
ABS HYDRAULIC CONTROL UNIT:
Hydraulic Tube Fitting
Type................ SAE45ÉInverted Flare
All Tube Nut Threads............7/16 in.±24
PROPORTIONING VALVE:
Material.......................Aluminum
Function.....Hydraulic Pressure Proportioning
BRAKE FASTENER TORQUE SPECIFICATIONS
DESCRIPTION TORQUE
BRAKE TUBES:
Tube Nuts............... 17N´m(145 in. lbs.)
MASTER CYLINDER:
Mounting Nuts.......... 28N´m(250 in. lbs.)
POWER BRAKE BOOSTER:
Mounting Nuts.......... 34N´m(300 in. lbs.)
DISC BRAKE CALIPER:
Caliper Banjo Bolt......... 48N´m(35ft.lbs.)
Guide Pin Bolts.......... 22N´m(192 in. lbs.)
Bleeder Screw........... 15N´m(125 in. lbs.)
WHEEL CYLINDER (REAR):
Mounting Bolts.......... 13N´m(115in.lbs.)
Bleeder Screw............ 10N´m(80in.lbs.)
DRUM BRAKE SHOE SUPPORT PLATE
(REAR):
Mounting Bolts........... 75N´m(55ft.lbs.)
DISC BRAKE ADAPTER (REAR):
Mounting Bolts........... 75N´m(55ft.lbs.)
HUB AND BEARING (REAR):
Retaining Nut.......... 217N´m(160 ft. lbs.)
PARKING BRAKE:
Lever Mounting Nuts..... 28N´m(250 in. lbs.)
TIRE AND WHEEL:
Wheel Mounting Nut...........109±150 N´m
(80±110 ft. lbs.)
INTEGRATED CONTROL UNIT:
Mounting Bolts........... 11N´m(97in.lbs.)
CAB Mounting bolts........ 2N´m(17in.lbs.)
Bracket-to-Frame Rail Bolts.......... 23N´m
(200 in. lbs.)
WHEEL SPEED SENSOR:
Head Mounting bolt...... 12N´m(105 in. lbs.)
PLBRAKES 5 - 63

ANTILOCK BRAKE SYSTEM
TABLE OF CONTENTS
page page
DESCRIPTION AND OPERATION
ANTILOCK BRAKE SYSTEM OPERATION......65
ANTILOCK BRAKE SYSTEM COMPONENTS....66
ELECTRONIC BRAKE DISTRIBUTION.........69
TRACTION CONTROL SYSTEM..............70
HYDRAULIC CIRCUITS AND VALVE
OPERATION...........................71
DIAGNOSIS AND TESTING
SERVICE WARNINGS AND CAUTIONS........74
ABS GENERAL DIAGNOSTICS INFORMATION . . 74
ABS WIRING DIAGRAM INFORMATION........74
ABS VEHICLE TEST DRIVE.................74
ABS ELECTRONIC DIAGNOSIS..............75
TONE WHEEL...........................76
BRAKE FLUID CONTAMINATION.............76
SERVICE PROCEDURES
BRAKE FLUID LEVEL CHECKING............77ANTILOCK BRAKE SYSTEM BLEEDING.......77
MASTER CYLINDER BLEEDING.............77
REMOVAL AND INSTALLATION
SERVICE WARNINGS AND CAUTIONS........78
MASTER CYLINDER......................78
INTEGRATED CONTROL UNIT...............79
WHEEL SPEED SENSOR (FRONT)...........81
WHEEL SPEED SENSOR (REAR)............83
DISASSEMBLY AND ASSEMBLY
INTEGRATED CONTROL UNIT...............84
SPECIFICATIONS
TONE WHEEL RUNOUT....................85
WHEEL SPEED SENSOR-TO-TONE WHEEL
CLEARANCE...........................85
BRAKE FASTENER TORQUE
SPECIFICATIONS.......................85
DESCRIPTION AND OPERATION
ANTILOCK BRAKE SYSTEM OPERATION
This section covers the physical and operational
descriptions, and the on-car service procedures for
the Mark 20e Antilock Brake System (ABS) with
traction control. It is the only antilock brake system
available on this vehicle.
The purpose of the antilock brake system is to pre-
vent wheel lockup under braking conditions on virtu-
ally any type of road surface. Antilock braking is
desirable because a vehicle that is stopped without
locking the wheels retains directional stability and
some steering capability. This allows the driver to
retain greater control of the vehicle during braking.
The traction control system reduces wheel slip and
maintains traction at the driving speeds below 56
kph (35 mph) when road conditions call for traction
assistance. Refer to TRACTION CONTROL SYSTEM
in this section for more information.
Vehicles equipped with ABS use electronic brake
distribution (EBD) to balance front-to-rear braking
when the brakes are applied in the partial braking
range. Refer to ELECTRONIC BRAKE DISTRIBU-
TION in this section for more information.
There are a few performance characteristics of the
Mark 20e Antilock Brake System that may at first
seem abnormal, but in fact are normal. These char-
acteristics are described below.
NORMAL BRAKING
Under normal braking conditions, the ABS func-
tions the same as a standard base brake system with
a diagonally split master cylinder and conventional
vacuum assist.
ABS BRAKING
ABS operation is available at all vehicle speeds
above 3±5 mph. If a wheel locking tendency is
detected during a brake application, the brake sys-
tem enters the ABS mode. During ABS braking,
hydraulic pressure in the four wheel circuits is mod-
ulated to prevent any wheel from locking. Each
wheel circuit is designed with a set of electric sole-
noids to allow modulation, although for vehicle sta-
bility, both rear wheel solenoids receive the same
electrical signal. Wheel lockup may be perceived at
the very end of an ABS stop and is considered nor-
mal.
During an ABS stop, the brakes hydraulic system
is still diagonally split. However, the brake system
pressure is further split into four control channels.
During antilock operation of the vehicle's brake sys-
tem, the wheels are controlled independently and are
on separate control channels.
The system can build, hold and release pressure at
each wheel, depending on signals generated by the
wheel speed sensors (WSS) at each wheel and
received at the controller antilock brake (CAB).
PLBRAKES 5 - 65

NOTE: It is not necessary to bleed the entire
hydraulic system after replacing just the master cyl-
inder unless the brake system has been open to air
for an excessive amount of time or air is present in
the lines. Only the master cylinder must be bled
and filled.
REMOVAL AND INSTALLATION
SERVICE WARNINGS AND CAUTIONS
Review this entire section prior to performing any
mechanical work on a vehicle equipped with ABS.
This section contains information on precautions per-
taining to potential component damage, vehicle dam-
age and personal injury which could result when
servicing an ABS equipped vehicle.
CAUTION: Only the recommended jacking or hoist-
ing positions for this vehicle are to be used when-
ever it is necessary to lift a vehicle. Failure to raise
a vehicle from the recommended locations could
result in lifting a vehicle by the hydraulic control
unit mounting bracket. Lifting a vehicle by the
hydraulic control unit mounting bracket will result
in damage to the mounting bracket and the hydrau-
lic control unit.
CAUTION: An attempt to remove or disconnect cer-
tain system components may result in improper
system operation. Only those components with
approved removal and installation procedures in
this manual should be serviced.CAUTION: Brake fluid will damage painted sur-
faces. If brake fluid is spilled on any painted sur-
faces, wash off with water immediately.
CAUTION: When performing any service procedure
on a vehicle equipped with ABS do not apply a
12-volt power source to the ground circuit of the
pump motor in the HCU. Doing this will damage the
pump motor and will require replacement of the
entire HCU.
CAUTION: If welding work is to be performed on
the vehicle, using an electric arc welder, the CAB
connector should be disconnected during the weld-
ing operation.
CAUTION: The CAB 25-way connector should never
be connected or disconnected with the ignition
switch in the ON position.
Many components of the ABS System are not ser-
viceable and must be replaced as an assembly. Do not
disassemble any component which is not designed to
be serviced.
MASTER CYLINDER
NOTE: Before proceeding with this procedure,
review SERVICE WARNINGS AND CAUTIONS at the
beginning of REMOVAL AND INSTALLATION in this
section.
REMOVAL
CAUTION: The vacuum in the power brake booster
must be pumped down before removing the master
cylinder to prevent the booster from sucking in any
contamination. This can be done by pumping the
brake pedal while the engine is not running until a
firm brake pedal is achieved.
(1) With the engine not running, pump the brake
pedal 4-5 strokes until the pedal feel is firm.
(2) Disconnect the negative (ground) cable from
the battery and isolate the cable.
(3) Disconnect the positive cable from the battery,
then remove the battery from the battery tray. There
is one nut securing the clamp on the backside of the
battery holding it in place.
(4) Disconnect the wiring harness connector from
the brake fluid level switch on the master cylinder
reservoir (Fig. 12).
Fig. 11 Bleeding Master Cylinder
1 ± WOODEN DOWEL
2 ± MASTER CYLINDER
5 - 78 BRAKESPL
SERVICE PROCEDURES (Continued)

(5) Disconnect the primary and secondary brake
tubes from master cylinder (Fig. 12). Install plugs in
the master cylinder outlet ports.
(6) Clean the area around where the master cylin-
der attaches to the power brake booster using a suit-
able brake cleaner such as MopartBrake Parts
Cleaner or an equivalent.
(7) Remove the 2 nuts attaching master cylinder to
power brake booster (Fig. 12).
(8) Slide the master cylinder straight out of the
power brake booster.
INSTALLATION
NOTE: The master cylinder must be bled before
installing it on the vehicle.
(1) Bleed the master cylinder before installing it
on the vehicle. Refer to MASTER CYLINDER
BLEEDING in SERVICE PROCEDURES within this
section of this service manual group.
(2) Wipe the face of the power brake booster clean
where the master cylinder seal comes in contact
when it's installed. Do not get any cleaner or debris
inside the booster.(3) Position the master cylinder on the studs of
power brake vacuum booster aligning the booster
push rod with the master cylinder push rod. Care-
fully push the master cylinder onto the studs until it
contacts the face of the booster.
(4) Install the two master cylinder mounting nuts
(Fig. 12). Tighten the mounting nuts to a torque of
28 N´m (250 in. lbs.).
(5) Connect the primary and secondary brake
tubes to the master cylinder primary and secondary
ports (Fig. 12). Tighten the nuts to a torque of 17
N´m (145 in. lbs.).
(6) Install the wiring harness connector on the
master cylinder reservoir fluid level switch.
(7) Install the battery and clamp in place.
(8) Connect the positive, then the negative
(ground) cable on the battery.
(9) Fill the master cylinder to the proper fill level.
(10) Road test the vehicle to ensure proper opera-
tion of the base and antilock brake systems.
INTEGRATED CONTROL UNIT
NOTE: Before proceeding with this procedure,
review SERVICE WARNINGS AND CAUTIONS at the
beginning of REMOVAL AND INSTALLATION in this
section.
REMOVAL
(1) Using a brake pedal holder, depress the brake
pedal past its first one inch of travel and hold it in
this position (Fig. 13). This will isolate the master
cylinder from the brake hydraulic system and will
not allow the brake fluid to drain out of the master
cylinder reservoir.
(2) Disconnect negative (ground) cable from the
battery and isolate the cable.
(3) Disconnect the positive cable from the battery,
then remove the battery from the battery tray. There
is one nut securing the clamp on the backside of the
battery holding it in place.
(4) Remove the one nut and one bolt securing the
air cleaner box in place, then disconnect the wiring
harness connector at the air inlet sensor.
(5) Lift the air cleaner box upward enough to clear
its grommeted alignment post (Fig. 14), then move
the air cleaner box forward just enough to access the
battery tray mounting bolts.
(6) Remove the 2 bolts, then the 2 nuts mounting
the battery tray to its bracket (Fig. 14). Remove the
battery tray.
Fig. 12 Master Cylinder
1 ± POWER BRAKE BOOSTER
2 ± CONNECTOR
3 ± BRAKE FLUID LEVEL SWITCH
4 ± MOUNTING NUTS
5 ± SECONDARY BRAKE TUBE
6 ± PRIMARY BRAKE TUBE
PLBRAKES 5 - 79
REMOVAL AND INSTALLATION (Continued)

Radiator cooling fan control operation is accomplished
two ways. The fan always runs when the air condition-
ing compressor clutch is engaged. In addition to this
control, the fan is turned on by the temperature of the
coolant which is sensed by the coolant temperature sen-
sor which sends the message to the Powertrain Control
Module (PCM). The PCM turns on the fan through a
fan relay by grounding the relay's coil. The fan relay is
located in the Power Distribution Center (PDC) (Fig. 4).
Refer to the label beneath the PDC cover for location of
fan relay.
The PCM will actuate the fan relay whenever the A/C
clutch is engaged regardless of coolant temperature and
vehicle speed. If the A/C clutch is not engaged, the PCM
will actuate the fan relay when the coolant temperature
reaches approximately (97É C) 207É F and turns off the
fan relay when the coolant temperature drops to
approximately (94ÉC) 201É F. The fan relay is also
turned off when the vehicle speed is above approxi-
mately 100 Km/h (62 MPH). Refer to Group 8W, Wiring
Diagrams for circuity provided.
If the cooling fan is inoperative or a Diagnostic
Trouble Code (DTC) related to fan control has been
set, refer to the appropriate Powertrain Diagnostic
Manual for complete diagnostic procedures.
COOLING SYSTEM PRESSURE CAP
The cooling system pressure cap is located on the cool-
ant outlet housing near the front of the cylinder head.
The cooling system will operate at higher than atmo-
spheric pressure. The higher pressure raises the coolant
boiling point, allowing increased radiator cooling capac-
ity. The pressure cap will release cooling system pres-
sure in a range of 97±124 kPa (14±18 psi).
A vent valve located in the center of the cap allows
a small amount of coolant flow from the coolant
reserve system (CRS) tank. This valve is spring
loaded in the closed position. However, it must be
free to open during system cool-down.If the valve is
stuck shut, the radiator hoses will collapse on
cool-down. Clean the vent valve (Fig. 5) to
ensure proper sealing function.
There is a gasket in the cap that seals to the top of
the filler neck so that vacuum is maintained to draw
coolant back into the system from the coolant reserve
system (CRS) tank.
Fig. 4 Power Distribution Center (PDC)
RADIATOR COOLING FAN OPERATION CHART
Cooling Fan Control
A/C Off
Fan On: 97É C (207É F)
Fan Off: 94É C (201É F)Vehicle Speed >
100 Km/h (62
MPH)
A/C On
Fan OnÐregardless of coolant temperature or vehicle
speed.
Fig. 5 Cooling System Pressure Cap
1 ± PRESSURE RATING
2 ± FILLER NECK SEAL
3 ± PRESSURE VALVE
4 ± VACUUM VENT VALVE (SHOWN IN SEALING POSITION)
7 - 4 COOLING SYSTEMPL
DESCRIPTION AND OPERATION (Continued)

CONDITION POSSIBLE CAUSE CORRECTION
TEMPERATURE GAUGE READS
HIGH OR ENGINE COOLANT
WARNING LAMP ILLUMINATES.
COOLANT MAY OR MAY NOT BE
LOST FROM SYSTEM. (CONT.)6. Poor seals at radiator cap. 6. (a) Check condition of cap and
cap seals. Refer to Radiator cap
Inspection. Replace cap if
necessary.
(b) Check condition of filler neck. If
neck is bent or damaged, replace
neck.
7. Coolant level low in radiator, but
not in coolant recovery/reserve
container. This indicates the
radiator is not drawing coolant from
the coolant recovery/reserve
container as the engine cools. As
the engine cools, a vacuum is
formed inside the cooling system. If
the radiator cap seals are defective,
or the cooling system has a leak, a
vacuum cannot be formed.7. (a) Check condition of radiator
cap and cap seals. Replace cap if
necessary.
(b) Check condition of filler neck.
Replace if damaged.
(c) Check condition of hose from
filler neck to coolant container. It
should be tight at both ends without
any kinks or tears. Replace hose as
necessary.
(d) Check coolant recovery/reserve
container and hose for blockage.
Repair as necessary.
8. Freeze point of coolant not
correct. Mixture ratio may be too
rich.8. Check coolant concentration.
Refer to Coolant Concentration
Testing in this section. Adjust
glycol-to-water ration as required.
9. Coolant not flowing through
system.9. Check for coolant flow at filler
neck with some coolant removed,
engine warm, and thermostat open.
Coolant should be observed flowing
through filler neck. If flow is not
observed, determine reason for lack
of flow and repair as necessary.
10. Radiator or A/C condenser fins
are dirty or clogged.10. Clean obstruction from fins.
11. Radiator core is plugged or
corroded.11. Replace or re-core radiator.
12. Fuel or ignition system
problems.12. Refer to Fuel and Ignition
System groups for diagnosis. Also
refer to the appropriate Powertrain
Diagnostic Procedure manual.
13. Dragging Brakes. 13. Inspect brake system and repair
as necessary. Refer to Group 5,
Brakes for diagnosis.
14 Bug screen or other aftermarket
accessory is being used causing
reduced air flow.14. Remove bug screen or
accessory.
15. Thermostat partially or
completely closed. This is more
prevalent on high mileage vehicles.15. Check thermostat operation and
replace as necessary. Refer to
thermostat in this section for
procedure.
7 - 8 COOLING SYSTEMPL
DIAGNOSIS AND TESTING (Continued)