air suspension CHRYSLER CARAVAN 2003 Service Manual

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Introduction
0Lubrication & Maintenance
0aMaintenance Schedules
2Suspension
3Differential & Driveline
5Brakes
6Clutch
7Cooling
8AAudio
8BChime/Buzzer
8EElectronic Control Modules
8FEngine Systems
8GHeated Systems
8HHorn
8IIgnition Control
8JInstrument Cluster
8LLamps
8MMessage Systems
8NPower Systems
8ORestraints
8PSpeed Control
8QVehicle Theft Security
8RWipers/Washers
8WWiring
9Engine
11Exhaust System
13Frame & Bumpers
14Fuel System
19Steering
21Transmission/Transaxle
22Tires/Wheels
23Body
24Heating & Air Conditioning
25Emissions Control
Component and System Index
Service Manual Comment Forms (Rear of Manual)
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TOWING
STANDARD PROCEDURE - TOWING
WARNINGS AND CAUTIONS
WARNING: DO NOT ALLOW TOWING ATTACHMENT
DEVICES TO CONTACT THE FUEL TANK OR LINES,
FUEL LEAK CAN RESULT.
DO NOT LIFT OR TOW VEHICLE BY FRONT OR
REAR BUMPER.
DO NOT GO UNDER A LIFTED VEHICLE IF NOT
SUPPORTED PROPERLY ON SAFETY STANDS.
DO NOT ALLOW PASSENGERS TO RIDE IN A
TOWED VEHICLE.
USE A SAFETY CHAIN THAT IS INDEPENDENT
FROM THE TOWING ATTACHMENT DEVICE.
CAUTION: Do not damage brake lines, exhaust sys-
tem, shock absorbers, sway bars, or any other
under vehicle components when attaching towing
device to vehicle.
Do not secure vehicle to towing device by the use
of front or rear suspension or steering components.
Remove or secure loose or protruding objects from
a damaged vehicle before towing.
Refer to state and local rules and regulations before
towing a vehicle.
Do not allow weight of towed vehicle to bear on
lower fascia, air dams, or spoilers.
RECOMMENDED TOWING EQUIPMENT
To avoid damage to bumper fascia and air dams
use:
²FWD vehicles, use of a flat bed towing device or
a wheel lift is recommended (Fig. 7).
²AWD vehicles, a flat bed towing device or a
wheel lift and towing dolly is recommended (Fig. 7).
When using a wheel lift towing device, be sure the
disabled vehicle has at least 100 mm (4 in.) ground
clearance. If minimum ground clearance cannot be
reached, use a towing dolly. If a flat bed device is
used, the approach angle should not exceed 15
degrees.
GROUND CLEARANCE
CAUTION: If vehicle is towed with wheels removed,
install lug nuts to retain brake drums or rotors.
A towed vehicle should be raised until the lifted
wheels are a minimum 100 mm (4 in.) from the
ground. Be sure there is at least 100 mm (4 in.)
clearance between the tail pipe and the ground. If
necessary, remove the wheels from the front end ofthe vehicle and lower the front end closer to the
ground, to increase the ground clearance at the rear
of the vehicle. Install lug nuts on wheel attaching
studs to retain brake drums or rotors.
LOCKED VEHICLE TOWING
When a locked vehicle must be towed with the
front wheels on the ground, use a towing dolly or flat
bed hauler.
FLAT TOWING WITH TOW BAR
²Three speed automatic transaxle vehicles can be
flat towed at speeds not to exceed 40 km/h (25 mph)
for not more than 25 km (15 miles). The steering col-
umn must be unlocked and gear selector in neutral.
²Four speed electronic automatic transaxle vehi-
cles can be flat towed at speeds not to exceed 72
km/h (44 mph) for not more than 160 km (100 miles).
The steering column must be unlocked and gear
selector in neutral.
²AWD models should not be flat towed. For addi-
tional information, refer toRECOMMENDED TOW-
ING EQUIPMENTin this section.
FLAT BED TOWING TIE DOWNS
CAUTION: Do not tie vehicle down by attaching
chains or cables to suspension components or
engine mounts, damage to vehicle can result.
The vehicle can be tied to a flat bed device using
the two pair of front slots on the bottom surface of
the rails, behind the front wheels. The two pair of
rear slots on the bottom of the rail between the
bumper extension bolts and on the bottom of the rail
just rearward of the jounce bumper. Vehicles
equipped with a rear sway bar have brackets at this
location.
Fig. 7 RECOMMENDED TOWING
1 - WHEEL LIFT
2 - FLAT BED
RSLUBRICATION & MAINTENANCE0-17
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INSPECTION - STEERING KNUCKLE
Inspect the knuckle for the following:
²Cracks or breaks
²Dents or damage
²Stress marks indicating a bend
The front suspension knuckle is not a repairable
component of the vehicles front suspension. If bent,
broken or damaged in any way, do not attempt to
straighten or repair the steering knuckle. It must be
replaced.
If inspection leads to the hub and bearing, (Refer
to 2 - SUSPENSION/FRONT/HUB / BEARING -
DIAGNOSIS AND TESTING)
INSTALLATION - STEERING KNUCKLE
(1) If the hub and bearing needs to be installed in
the knuckle, place the hub and bearing squarely into
the center hole of the steering knuckle aligning the
threaded mounting holes of the hub and bearing with
the mounting holes in the steering knuckle. Install
the four mounting bolts and tighten them to a torque
of 65 N´m (45 ft. lbs.).
CAUTION: Before installing the knuckle on the ball
joint stud, wipe the ball joint stud and knuckle con-
tact area free of any grease or debris, otherwisedamage to the knuckle can occur. Use a clean shop
cloth with MoparTBrake Parts Cleaner applied to it
for proper cleaning. Do not spray the stud directly.
(2) Place the knuckle on the ball joint stud.
(3) Install a NEW steering knuckle to ball joint
stud nut. Tighten the nut by holding ball joint stud
with hex wrench while turning nut with a wrench
(Fig. 15). Using a crowsfoot wrench on a torque
wrench, tighten the nut to a torque of 108 N´m (80 ft.
lbs.).
(4) Slide driveshaft stub axle into hub and bearing
assembly.
CAUTION: The steering knuckle to strut assembly
attaching bolts are serrated and must not be turned
during installation. Install nuts while holding bolts
stationary in the steering knuckle.
CAUTION: If the vehicle being serviced is equipped
with eccentric strut assembly attaching bolts, the
eccentric bolt must be installed in the bottom (slot-
ted) hole on the strut clevis bracket (Fig. 16).
NOTE: The strut clevis-to-steering knuckle bolts are
installed differently on each side. Left hand side
bolts are to be installed from vehicle rear to front.
Right side bolts are to be installed from vehicle
front to rear.
(5) Install steering knuckle in clevis bracket of
strut damper assembly. Install the strut clevis-to-
steering knuckle attaching bolts. Tighten both bolts
to a torque of 81 N´m (60 ft. lbs.) plus an additional
1/4 (90É) turn.
Fig. 14 Using C-4150A To Release Ball Joint
1 - ALUMINUM KNUCKLE
2 - SPECIAL TOOL C-4150A
3 - LOWER CONTROL ARM
4 - NUT INSTALLED ON BALL JOINT STEMFig. 15 Ball Joint Nut Installation
1 - KNUCKLE
2 - BALL JOINT STUD
3 - LOWER CONTROL ARM
RSFRONT SUSPENSION2-9
KNUCKLE (Continued)
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DISASSEMBLY - LOWER CONTROL ARM
(REAR BUSHING - HYDRO)
(1) Remove the lower control arm from the front
suspension cradle. (Refer to 2 - SUSPENSION/
FRONT/LOWER CONTROL ARM - REMOVAL)
(2) Mount the lower control arm in a visewithout
using excessive clamping force.
(3) Install Remover, Special Tool 8460, on hydro-
bushing as shown (Fig. 24). Removal Pin, Special
Tool 8460±3, must extend though hole in center of
bushing rear.
(4) Tighten forcing screw of Bridge (Special Tool
8460±1), removing bushing from lower control arm.
INSPECTION - LOWER CONTROL ARM
Inspect lower control arm for signs of damage from
contact with the ground or road debris. If lower con-
trol arm shows any sign of damage, inspect lower
control arm for distortion. Do not attempt to repair
or straighten a broken or bent lower control arm. If
damaged, the lower control arm casting is serviced
only as a complete component.
Inspect both lower control arm isolator bushings
for severe deterioration, and replace as required.
Inspect the rear hydro-bushing for seepage. Both
type rear bushings are serviceable. If the front bush-
ing fails, the lower control arm must be replaced.
Inspect and test the ball joint per the procedure
listed in Lower Ball Joint. (Refer to 2 - SUSPEN-
SION/FRONT/LOWER BALL JOINT - DIAGNOSIS
AND TESTING)
ASSEMBLY
ASSEMBLY - LOWER CONTROL ARM (REAR
BUSHING - STANDARD)
CAUTION: Do not apply grease or any other type of
lubricant other than the silicone lubricant specified
below to the control arm bushing.
(1) Apply Mopar Silicone Spray Lube or an equiv-
alent, to the hole in lower control arm rear bushing.
This will aid in the installation of the bushing on the
lower control arm.
(2) With the lower control arm held securely in a
vise, install bushing on lower control arm. Install
bushing by pushing and rocking the bushing until it
is fully installed on lower control arm. Be sure that
when bushing is installed it is past the upset on the
end of the lower control arm (Fig. 25).
(3) The rear bushing of the lower control arm,
when correctly installed, is to be positioned on the
lower control arm as shown (Fig. 25).
(4) Install lower control arm on vehicle. (Refer to 2
- SUSPENSION/FRONT/LOWER CONTROL ARM -
INSTALLATION)
ASSEMBLY - LOWER CONTROL ARM (REAR
BUSHING - HYDRO)
CAUTION: Do not apply grease or any other type of
lubricant to the arm stem where the bushing is to
be mounted. Such action will reduce proper bush-
ing adhesion to arm.
Fig. 24 HYDRO-BUSHING REMOVAL
1 - REMOVAL PIN (8460-3)
2 - BRIDGE (8460-1)
3 - HYDRO-BUSHING
4 - LOWER CONTROL ARM
Fig. 25 Correctly Installed Lower Control Arm
Bushing
1 - ROUND SURFACE OF BUSHING
2 - LOWER CONTROL ARM
3 - LOWER CONTROL ARM REAR BUSHING
4 - UPSET
5 - FLAT SURFACE OF BUSHING
2 - 14 FRONT SUSPENSIONRS
LOWER CONTROL ARM (Continued)
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CONDITION POSSIBLE CAUSES CORRECTION
Excessive Steering Effort 1. Low tire pressure 1. Inflate all tires to recommended
pressure
2. Lack of lubricant in steering gear 2. Replace steering gear
3. Low power steering fluid level 3. Fill power steering fluid reservoir to
correct level
4. Loose power steering pump drive
belt4. Correctly adjust power steering pump
drive belt
5. Lack of lubricant in ball joints 5. Lubricate or replace ball joints
6. Steering gear malfunction 6. Replace steering gear
7. Lack of lubricant in steering coupler 7. Replace steering coupler
STANDARD PROCEDURE
STANDARD PROCEDURE - WHEEL ALIGNMENT
PRE-WHEEL ALIGNMENT INSPECTION
Before any attempt is made to change or correct
the wheel alignment, the following inspection and
necessary corrections must be made to ensure proper
alignment.
(1) Verify that the fuel tank is full of fuel. If the
tank is not full, the reduction in weight will affect
the curb height of the vehicle and the alignment
angles.
(2) The passenger and luggage compartments of
the vehicle should be free of any load that is not fac-
tory equipment.
(3) Check the tires on the vehicle. All tires must be
the same size and in good condition with approxi-
mately the same amount of tread wear. Inflate all
the tires to the recommended air pressure.
(4) Check the front wheel and tire assemblies for
excessive radial runout.
(5) Inspect lower ball joints and all steering link-
age for looseness, binding, wear or damage. Repair as
necessary.
(6) Check suspension fasteners for proper torque
and retighten as necessary.
(7) Inspect all suspension component rubber bush-
ings for signs of wear or deterioration. Replace any
faulty bushings or components before aligning the
vehicle.
(8) Check the vehicle's curb height to verify it is
within specifications. Refer to Curb Height Measure-
ment.
WHEEL ALIGNMENT SETUP
(1) Position the vehicle on an alignment rack.
(2) Install all required alignment equipment on
the vehicle per the alignment equipment manufactur-
er's instructions. On this vehicle, a four-wheel align-
ment is recommended.NOTE: Prior to reading the vehicle's alignment
readouts, the front and rear of vehicle should be
jounced. Induce jounce (rear first, then front) by
grasping the center of the bumper and jouncing
each end of vehicle an equal number of times. The
bumper should always be released when vehicle is
at the bottom of the jounce cycle.
(3) Read the vehicle's current front and rear align-
ment settings. Compare the vehicle's current align-
ment settings to the vehicle specifications for camber,
caster and toe-in. (Refer to 2 - SUSPENSION/
WHEEL ALIGNMENT - SPECIFICATIONS)
(4) If front camber and caster are not within spec-
ifications, proceed to CAMBER AND CASTER below.
If caster and camber are within specifications, pro-
ceed to TOE which can be found following CAMBER
AND CASTER. Rear camber, caster and toe are not
adjustable. If found not to be within specifications,
reinspect for damaged suspension or body compo-
nents and replace as necessary.
CAMBER AND CASTER
Camber and caster settings on this vehicle are
determined at the time the vehicle is designed, by
the location of the vehicle's suspension components.
This is referred to as NET BUILD. The result is no
required adjustment of camber and caster after the
vehicle is built or when servicing the suspension
components. Thus, when performing a wheel align-
ment, caster and camber are not normally considered
adjustable angles. Camber and caster should be
checked to ensure they meet vehicle specifications.
If front camber is found not to meet alignment
specifications, it can be adjusted using an available
camber adjustment bolt package. Before installing a
camber adjustment bolt package on a vehicle found
to be outside the specifications, inspect the suspen-
sion components for any signs of damage or bending.
RSWHEEL ALIGNMENT2-51
WHEEL ALIGNMENT (Continued)
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CONDITION POSSIBLE CAUSES CORRECTION
EXCESSIVE PEDAL
TRAVEL (ONE FRONT
WHEEL LOCKS UP
DURING HARD BRAKING)1. One of the two hydraulic circuits
to the front brakes is malfunctioning.1. Inspect system for leaks. Check
master cylinder for internal malfunction.
PEDAL PULSATES/
SURGES DURING
BRAKING1. Rear brake drum out of round or
disc brake rotor has excessive
thickness variation.1. Isolate condition as rear or front.
Reface or replace brake drums or
rotors as necessary.
PEDAL IS SPONGY 1. Air in brake lines. 1. Bleed brakes.
2. Power brake booster runout
(vacuum assist).2. Check booster vacuum hose and
engine tune for adequate vacuum
supply. Refer to power brake booster
diagnosis and testing.
PREMATURE REAR
WHEEL LOCKUP1. Contaminated brake shoe linings. 1. Inspect and clean, or replace shoes.
Repair source of contamination.
2. Inoperative proportioning valve
(non-ABS vehicles).2. Refer to proportioning valve
diagnosis and testing. Replace valve as
necessary.
3. Improper power brake booster
assist.3. Refer to power brake booster in the
diagnosis and testing section.
STOP/BRAKE LAMPS
S TAY O N1. Brake lamp switch out of
adjustment.1. Replace brake lamp switch.
2. Brake pedal binding. 2. Inspect and replace as necessary.
3. Obstruction in pedal linkage. 3. Remove obstruction.
4. Power Brake Booster not allowing
pedal to return completely.4. Replace power brake booster.
VEHICLE PULLS TO
RIGHT OR LEFT ON
BRAKING1. Frozen brake caliper piston. 1. Replace frozen piston or caliper.
Bleed brakes.
2. Contaminated brake shoe lining. 2. Inspect and clean, or replace shoes.
Repair source of contamination.
3. Pinched brake lines. 3. Replace pinched line.
4. Leaking piston seal. 4. Replace piston seal or brake caliper.
5. Suspension problem. 5. Refer to the Suspension group.
PARKING BRAKE -
EXCESSIVE HANDLE
TRAVEL1. Rear drum brakes or rear disc
brake parking brake shoes out of
adjustment.1. Adjust rear drum brake shoes, or
rear parking brake shoes on vehicles
with rear disc brakes.
STANDARD PROCEDURE - BASE BRAKE
BLEEDING
NOTE: This bleeding procedure is only for the vehi-
cle's base brakes hydraulic system. For bleeding
the antilock brakes hydraulic system, (Refer to 5 -
BRAKES - ABS - STANDARD PROCEDURE)CAUTION: Before removing the master cylinder
cover, thoroughly clean the cover and master cylin-
der fluid reservoir to prevent dirt and other foreign
matter from dropping into the master cylinder fluid
reservoir.
RSBRAKES - BASE5-7
BRAKES - BASE (Continued)
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Use only brake fluid that was stored in a tightly-
sealed container.
DO NOTuse petroleum-based fluid because seal
damage will result. Petroleum based fluids would be
items such as engine oil, transmission fluid, power
steering fluid etc.
SPECIFICATIONS
BRAKE FLUID
The brake fluid used in this vehicle must conform
to DOT 3 specifications (DOT 4 and DOT 4+ are
acceptable) and SAE J1703 standards. No other type
of brake fluid is recommended or approved for usage
in the vehicle brake system. Use only MopartBrake
Fluid or 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 of brake fluid 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.
JUNCTION BLOCK
DESCRIPTION - NON-ABS JUNCTION BLOCK
A junction block is used on vehicles that are not
equipped with antilock brakes (ABS). The junction
block mounts in the same location as the integrated
control unit (ICU) does on vehicles equipped with
ABS. This allows for use of the same brake tube con-
figuration on all vehicles. The junction block is
located on the driver's side of the front suspension
cradle/crossmember below the master cylinder (Fig.
45).
It has six threaded ports to which the brake tubes
connect. Two are for the primary and secondary
brake tubes coming from the master cylinder. The
remaining four are for the chassis brake tubes going
to each brake assembly.
OPERATION - NON-ABS JUNCTION BLOCK
The junction block distributes the brake fluid com-
ing from the master cylinder primary and secondary
ports to the four chassis brake tubes leading to the
brakes at each wheel. Since the junction blockmounts in the same location as the ABS integrated
control unit (ICU), it allows for the common use of
brake tubes going to the brakes whether the vehicle
is equipped with or without ABS.
NOTE: Although the brake tubes coming from the
master cylinder to the junction block or ABS ICU
may appear to be the same, they are not. They are
unique to each brake system application.
REMOVAL - NON-ABS JUNCTION BLOCK
(1) Using a brake pedal depressor, move and lock
the brake pedal to a position past its first 1 inch of
travel. This will prevent brake fluid from draining
out of the master cylinder when the brake tubes are
removed from the junction block.
(2) Disconnect the battery negative cable.
(3) If the vehicle is equipped with speed control,
perform the following:
(a) Disconnect the battery positive cable.
(b) Remove the battery (Refer to 8 - ELECTRI-
CAL/BATTERY SYSTEM/BATTERY - REMOVAL).
(c) Disconnect the vacuum hose connector at the
tank built into the battery tray.
(d) Remove the screw securing the coolant filler
neck to the battery tray.
(e) Remove the battery tray (Refer to 8 - ELEC-
TRICAL/BATTERY SYSTEM/TRAY - REMOVAL).
(f) Remove the fasteners and move the speed
control servo off to the side, out of the way.
CAUTION: Before removing the brake tubes from
the junction block, the junction block and the brake
tubes must be thoroughly cleaned. This is required
to prevent contamination from entering the brake
hydraulic system.
(4) Remove the four chassis brake tubes from the
top of the junction block (Fig. 45).
(5) Remove the primary and secondary brake
tubes from the top of the junction block.
(6) Remove the bolts attaching the junction block
mounting bracket to the front suspension crossmem-
ber (Fig. 45), then remove the junction block.
INSTALLATION - NON-ABS JUNCTION BLOCK
(1) Install the junction block and mounting bracket
on the front suspension crossmember (Fig. 45).
Install the mounting bolts and tighten to a torque of
28 N´m (250 in. lbs.).
(2) Install the primary and secondary brake tubes
from the master cylinder in their ports. Tighten tube
nuts to a torque of 17 N´m (145 in. lbs.).Take care
not to twist tubes when tightening tube nuts.
They must be properly positioned to allow free
RSBRAKES - BASE5-33
FLUID (Continued)
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movement with rubber isolated suspension
crossmember.
(3) Install the four chassis brake tubes into the
outlet ports of the junction block. Tighten all 6 tube
nuts to a torque of 17 N´m (145 in. lbs.).
(4) If the vehicle is equipped with speed control,
perform the following:
(a) Install the speed control servo with its
mounting nuts.
(b) Connect the wiring harness to the speed con-
trol servo.
(c) Install the battery tray (Refer to 8 - ELEC-
TRICAL/BATTERY SYSTEM/TRAY - INSTALLA-
TION).
(d) Install the screw securing the coolant filler
neck to the battery tray.
(e) Reconnect the vacuum hose connector at the
tank built into the battery tray.
(f) Install the battery (Refer to 8 - ELECTRI-
CAL/BATTERY SYSTEM/BATTERY - INSTALLA-
TION).
(g) Install the battery shield.
(5) Remove the brake pedal holder.
(6) Connect negative cable back on negative post of
the battery.
(7) Bleed the brake system thoroughly to ensure
that all air has been expelled from the hydraulic sys-
tem. (Refer to 5 - BRAKES - STANDARD PROCE-
DURE).
(8) Road test the vehicle to verify proper operation
of the brake system.
MASTER CYLINDER
DESCRIPTION
DESCRIPTION
The master cylinder is located on the power brake
booster in the engine compartment on the driver's
side (Fig. 46). This vehicle uses 3 different master
cylinders. Master cylinder usage depends on what
type of brake system the vehicle is equipped with.
CAUTION: Master cylinders are not interchangeable
between systems. Performance and stopping dis-
tance issues will result if the incorrect master cyl-
inder is installed on the vehicle.
For information on master cylinder application,
bore and type, view the following table:
BRAKE SYSTEMMASTER CYLINDER
BORE/TYPE
Disc/Drum - ABS23.8 mm (15/16 in.)
Conventional
Compensating Port
Disc/Drum - Non-ABS23.8 mm (15/16 in.)
Conventional
Compensating Port
Disc/Disc - ABS25.4 mm (1.0 in.)
Conventional
Compensating Port
Disc/Disc ABS With
Traction Control25.4 mm (1.0 in.) Dual
Center Port
Fig. 45 NON-ABS JUNCTION BLOCK
1 - MASTER CYLINDER
2 - JUNCTION BLOCK
3 - SUSPENSION CROSSMEMBER
4 - MOUNTING BOLTS
Fig. 46 Master Cylinder And Booster Location
1 - MASTER CYLINDER
2 - POWER BRAKE BOOSTER
5 - 34 BRAKES - BASERS
JUNCTION BLOCK (Continued)
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Here is how the height sensing proportioning valve
differs from a standard proportioning valve. As the
height of the rear suspension changes, the height
sensing portion of the proportioning valve changes
the split point of the proportioning valve. When the
height of the rear suspension is low, the proportion-
ing valve interprets this as extra load and the split
point of the proportioning valve is raised to a higher
pressure to allow for more rear braking. When the
height of the rear suspension is high, the proportion-
ing valve interprets this as a light load and the split
point of the proportioning valve is lowered to a lower
pressure and rear braking is reduced.
The height sensing proportioning valve regulates
the pressure by sensing the load condition of the
vehicle through the movement of the proportioning
valve actuator lever (Fig. 72). As the position of the
rear axle changes, depending on the load the vehicle
is carrying, the movement is transferred to the pro-
portioning valve. The proportioning valve adjusts the
hydraulic pressure accordingly.
The height sensing proportioning valve allows the
brake system to maintain the optimal front to rear
brake balance regardless of the vehicle load condi-
tion. Under a light load condition, hydraulic pressure
to the rear brakes is minimized. As the rear load con-
dition increases, so does the hydraulic pressure to
the rear brakes.
DIAGNOSIS AND TESTING - PROPORTIONING
VALVE (HEIGHT SENSING)
CAUTION: The use of aftermarket load leveling or
load capacity increasing devices on this vehicle is
prohibited. Using air shock absorbers or helpersprings 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.
When a premature rear wheel skid is obtained on a
brake application, it may be an indication that the
hydraulic pressure to the rear brakes is above the
specified output from the proportioning valve. This
condition indicates a possible malfunction of the
height sensing proportioning valve, which will
require testing to verify that it is properly controlling
the hydraulic pressure allowed to the rear brakes.
Premature rear wheel skid may also be caused by
contaminated front or rear brake linings.
Prior to testing a proportioning valve for function,
check that all tire pressures are correct. Also, ensure
the front and rear brake linings are in satisfactory
condition.It is also necessary to verify that the
brakes shoe assemblies on a vehicle being
tested are either original equipment manufac-
turers (OEM) or original replacement brake
shoe assemblies meeting the OEM lining mate-
rial specification. This vehicles brake system is
not balanced for aftermarket brake shoe assem-
bly lining material.
If both front and rear brakes check OK, proceed
with the following test procedure for the height sens-
ing proportioning valve.
(1) Road test the vehicle to determine which rear
wheel brake is exhibiting premature wheel skid.
(2) Raise vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE)
(3) Remove the chassis brake tube going to the
rear brake in question at the proportioning valve.
Remove the chassis brake tube coming from the junc-
tion block at the proportioning valve (Fig. 73).
(4) Install the appropriate fittings from Pressure
Test Fittings, Special Tool 6833, into the open ports
of the proportioning valve.
(5) Install the previously removed brake lines into
the Pressure Test Fittings. Tighten all tube nuts to
17 N´m (145 in. lbs.).
(6) Install a pressure gauge from Gauge Set, Spe-
cial Tool C-4007-A into the open port on each pres-
sure test fitting. Bleed air out of hose from pressure
test fittings to pressure gauges at the pressure
gauges. Then bleed air out of the brake line being
tested at that rear wheel brake bleeder.
NOTE: Actuator rod is a linear spring and is meant
to flex by design. When rod is raised, it will have
some curvature to it.
Fig. 72 HEIGHT SENSING PROPORTIONING VALVE
1 - PROPORTIONING VALVE
2 - ACTUATOR LEVER
3 - AXLE BRACKET
4 - REAR AXLE
RSBRAKES - BASE5-49
PROPORTIONING VALVE (Continued)
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SUPPORT PLATE - DRUM
BRAKE
REMOVAL
(1) Using a brake pedal depressor, move and
secure brake pedal to a position past its first 1 inch
of travel. This will prevent brake fluid from draining
out of master cylinder when brake tube is remove
from wheel cylinder.
(2) Raise vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE).
(3) Remove wheel and tire assembly.
(4) Disconnect brake tube from rear of wheel cylin-
der. Cap open ends
(5) Remove brake drum.
(6) Remove brake shoes from brake support plate.
(Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/
BRAKE PADS/SHOES - REMOVAL).
(7) Remove the 2 bolts attaching the wheel cylin-
der to the brake support plate.
(8) Remove the wheel cylinder from the brake sup-
port plate.
(9) Disconnect the park brake cable from the park
brake actuation lever.
(10) Using a suitable tool such as a 14 mm box
wrench (Fig. 84) or an aircraft type hose clamp, com-
press the flared legs on park brake cable retainer.
Then pull the park brake cable out of brake support
plate.
(11) Remove the rear hub and bearing. (Refer to 2
- SUSPENSION/REAR/HUB / BEARING -
REMOVAL)(12) Remove the rear brake support plate from the
rear axle.
INSTALLATION
(1) Install the 4 hub and bearing to axle mounting
bolts into the mounting holes in the flange of the
rear axle.
(2) Install the rear brake support plate on the 4
mounting bolts installed in the flange of the rear axle
(Fig. 85).
(3) Install the rear hub and bearing (and connect
wheel speed sensor where applicable) stopping short
of installing the brake drum. (Refer to 2 - SUSPEN-
SION/REAR/HUB / BEARING - INSTALLATION)
(4) Install the rear park brake cable into its
mounting hole in the rear brake support plate.
(5) Install the park brake cable on the park brake
actuation lever.
(6) Apply sealant such as Mopar Gasket-In-A-Tube
or equivalent around the wheel cylinder opening in
the brake support plate.
(7) Install wheel cylinder onto brake support.
Install and tighten the wheel cylinder to brake sup-
port plate attaching bolts to 8 N´m (75 in. lbs.)
torque.
(8) Install brake tube into wheel cylinder. Tighten
tube nut to a torque of 17 N´m (145 in. lbs.) torque.
(9) Install the rear brake shoes on the brake sup-
port plate. (Refer to 5 - BRAKES/HYDRAULIC/ME-
CHANICAL/BRAKE PADS/SHOES -
INSTALLATION).
(10) Install brake drum.
(11) Install wheel and tire.
(12) Tighten wheel stud nuts to 135 N´m (100 ft.
lbs.).
Fig. 84 Removing Park Brake Cable From Brake
Support Plate
1 - PARK BRAKE CABLE
2 - CABLE RETAINER
3 - 14 mm BOX WRENCH
4 - BRAKE SUPPORT PLATE
Fig. 85 Brake Support Plate Mounted On Bearing
Attaching Bolts
1 - REAR BRAKE SUPPORT PLATE
2 - HUB/BEARING MOUNTING BOLTS
5 - 56 BRAKES - BASERS
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