wheel CHRYSLER CARAVAN 2003 Owners Manual

(1) Depress the brake pedal past its first inch of
travel and hold it in this position using a brake pedal
depressor (holding) tool. This is done to isolate the
master cylinder from the brake hydraulic system dis-
allowing the brake fluid to completely drain out of
the brake fluid reservoir.
(2) Raise the vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE)
(3) Remove rear wheel and tire assembly from
vehicle.
(4) Remove the banjo bolt connecting the brake
hose to the brake caliper. There are two washers (one
on each side of the brake hose fitting) that will come
off with the banjo bolt. Discard these washers.
(5) Remove the disc brake caliper to adapter guide
pin bolts (Fig. 37).
(6) Remove rear caliper from adapter using the fol-
lowing procedure. First rotate front of caliper up
from the adapter. Then pull the rear of the caliper
and the outboard brake shoe anti-rattle clip out from
under the rear abutment on the adapter (Fig. 38).
(7) If the brake rotor requires removal, it can now
be removed by first removing the retainer clips from
the wheel mounting studs, then pulling the rotor
straight off the studs.
DISASSEMBLY - CALIPER PISTON AND SEAL
WARNING: UNDER NO CONDITION SHOULD HIGH
PRESSURE AIR EVER BE USED TO REMOVE A PIS-
TON FROM A CALIPER BORE. PERSONAL INJURY
COULD RESULT FROM SUCH A PRACTICE.NOTE: Before disassembling the brake caliper,
clean and inspect it. Refer to CLEANING AND
INSPECTION in this section.
NOTE: The safest way to remove the piston from
the caliper bore is to use the hydraulic pressure of
the vehicle's brake system.
(1) Following the removal procedure in DISC
BRAKE SHOES found in this section, remove the
caliper from the brake rotor and hang the assembly
on a wire hook away from rotor and body of the vehi-
cle so brake fluid cannot get on these components.
Remove the brake shoes, and place a small piece of
wood between the piston and caliper fingers.
(2) Carefully depress the brake pedal to hydrauli-
cally push piston out of its bore. Once completed,
apply and hold down the brake pedal to any position
beyond the first inch of pedal travel using a brake
pedal holding tool. This will prevent the fluid in the
master cylinder reservoir from completely draining
out.
(3) Disconnect the brake fluid flex hose from the
caliper assembly and remove it from the vehicle.
CAUTION: Do not use excessive force when clamp-
ing caliper in vise. Excessive vise pressure will
cause bore distortion.
(4) Mount the caliper in a vise equipped with pro-
tective jaws.
(5) Remove the piston dust boot from the caliper
and discard.
Fig. 37 Caliper Guide Pin Bolts
1 - DISC BRAKE CALIPER
2 - ADAPTER
3 - AXLE
4 - GUIDE PIN BOLTS
5 - DRIVESHAFT (AWD MODELS ONLY)
Fig. 38 Removing/Installing Caliper
1 - LIFT THIS END OF CALIPER AWAY FROM ADAPTER FIRST
2 - DISC BRAKE CALIPER
3 - ADAPTER ABUTMENT
4 - OUTBOARD BRAKE SHOE HOLD DOWN CLIP
5 - OUTBOARD BRAKE SHOE
6 - ROTOR
7 - ADAPTER
5 - 28 BRAKES - BASERS
DISC BRAKE CALIPER - REAR (Continued)
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(7) Reinstall the caliper on the vehicle and bleed
the brakes as necessary. Refer to Installation in this
section.
INSTALLATION - REAR DISC BRAKE CALIPER
(1) Completely retract caliper piston back into pis-
ton bore of the caliper.
(2) If removed, install the brake rotor on the hub,
making sure it is squarely seated on the face of the
hub.CAUTION: Use care when installing the caliper
assembly onto the adapter, so the caliper guide pin
bushings do not get damaged by the mounting
bosses.
(3) Carefully lower caliper and brake shoes over
rotor and onto the adapter using the reverse proce-
dure for removal (Fig. 38).
CAUTION: When installing guide pin bolts extreme
caution should be taken not to cross-thread the cal-
iper guide pin bolts.
(4) Install the caliper guide pin bolts. Tighten the
guide pin bolts to a torque of 35 N´m (26 ft. lbs.).
CAUTION: When connecting the brake hose to the
caliper, install new brake hose to caliper special
washers.
(5) Install the brake hose on the caliper. To do
this, first place one NEW special copper washer on
each side of the hose fitting, then slide the banjo bolt
through the fitting. Next, thread the banjo bolt into
the threaded port on the rear of the brake caliper.
Tighten the banjo bolt to a torque of 47 N´m (35 ft.
lbs.).
(6) Install the wheel and tire assembly.
Fig. 40 Installing New Piston Seal
1 - CALIPER
2 - PISTON SEAL
3 - SEAL GROOVE
Fig. 41 Installing Piston Into Caliper Bore
1 - BOOT
2 - PISTON
3 - CALIPER
Fig. 42 Installing Dust Boot
1 - HAMMER
2 - SPECIAL TOOL C-4171
3 - SPECIAL TOOL C-4689 or C-4842
4 - CALIPER
5 - 30 BRAKES - BASERS
DISC BRAKE CALIPER - REAR (Continued)
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(7) Tighten the wheel mounting stud nuts in
proper sequence until all nuts are torqued to half
specification. Then repeat the tightening sequence to
the full specified torque of 135 N´m (100 ft. lbs.).
(8) Lower the vehicle.
(9) Remove the brake pedal depressor (holding)
tool.
(10) Bleed the hydraulic brake circuit to the brake
caliper. (Refer to 5 - BRAKES - STANDARD PROCE-
DURE)
(11) Road test the vehicle and make several stops
to wear off any foreign material on the brakes and to
seat the brake shoe linings.
DISC BRAKE CALIPER
ADAPTER
REMOVAL - FRONT DISC BRAKE CALIPER
ADAPTER
(1) Raise vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE)
(2) Remove front wheel and tire assembly, disc
brake caliper and brake shoes. (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/BRAKE PADS/SHOES
- REMOVAL)
(3) Remove two bolts fastening adapter to steering
knuckle, then remove disc brake caliper adapter.
INSTALLATION - FRONT DISC BRAKE CALIPER
ADAPTER
(1) Place adapter over brake rotor and align
adapter mounting holes to knuckle.
CAUTION: Adapter mounting bolts have a special
DacrometTcoating applied to resist corrosion. If
mounting bolts need to be replaced, use only
MoparTreplacement parts.
(2) Install adapter mounting bolts and tighten to
169 N´m (125 ft. lbs.) torque.
(3) Install brake shoes, disc brake caliper and
wheel and tire assembly. (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/BRAKE PADS/SHOES -
INSTALLATION)
(4) Lower vehicle.
(5) Pump the brake pedal several times to set the
pads to the brake rotor.
(6) Check and adjust brake fluid level as neces-
sary.
DISC BRAKE CALIPER GUIDE
PINS
REMOVAL - DISC BRAKE CALIPER GUIDE PINS
(DISC/DRUM BRAKES)
(1) Raise the vehicle. Refer to HOISTING in
LUBRICATION AND MAINTENANCE.
(2) Remove the front tire and wheel assembly.
(3) Remove the two brake caliper guide pin bolts
(Fig. 43).
(4) Remove the disc brake caliper from the disc
brake caliper adapter and hang it out of the way
using wire or a bungee cord. Use care not to overex-
tend the brake hose when doing this.
(5) Remove the guide pins and boots from the
adapter as shown (Fig. 44).
INSTALLATION - DISC BRAKE CALIPER GUIDE
PINS (DISC/DRUM BRAKES)
(1) Lubricate the guide pins and inside the boots
with the packet supplied with the service kit, Syth-
eso GLK-1 lubricant or equivalent.
(2) Install the guide pins and boots in the adapter
as shown (Fig. 44). The boots have grooves built into
their inner lips to fit onto the pins and adapter.
CAUTION: Use care when installing the caliper onto
the disc brake adapter to avoid damaging the boots
on the caliper guide pins.
Fig. 43 Brake Caliper Mounting
1 - BRAKE HOSE
2 - ADAPTER MOUNTING BOLTS
3 - BANJO BOLT
4 - CALIPER GUIDE PIN BOLTS
RSBRAKES - BASE5-31
DISC BRAKE CALIPER - REAR (Continued)
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(3) Install the disc brake caliper over the brake
shoes on the brake caliper adapter.
(4) Align the caliper guide pin bolt holes with the
guide pins. Install the caliper guide pin bolts and
tighten them to a torque of 35 N´m (26 ft. lbs.) (Fig.
43).
(5) Install the tire and wheel assembly. Tighten
the wheel mounting nuts to a torque of 135 N´m (100
ft. lbs.).
(6) Lower the vehicle.
(7) Pump the brake pedal several times before
moving the vehicle to set the shoes to the brake
rotor.
DRUM
REMOVAL
(1) Raise the vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE).
(2) Remove the tire and wheel assembly from the
vehicle
(3) Remove the rear brake shoe adjusting hole
cover plug.
(4) Insert a thin screwdriver into brake adjusting
hole and hold adjusting lever away from notches of
adjusting screw star wheel.
(5) Insert another thin screwdriver into brake
adjusting hole and engage notches of brake adjusting
screw star wheel. Release brake adjustment by pry-
ing down with adjusting tool.
(6) Remove rear brake drum from rear hub/bear-
ing assembly.NOTE: It may be necessary to insert M8 X 1.25 MM
bolts into the two removal holes on the drum to
force the drum off the hub.
INSTALLATION
(1) Adjust brake shoe assemblies so as not to inter-
fere with brake drum installation.
(2) Install the rear brake drums on the hubs.
(3) Adjust drum brake shoes as necessary per pro-
cedure found in the Adjustment section of this ser-
vice manual group (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/DRUM -
ADJUSTMENTS).
(4) Install wheel and tire assembly.
(5) Tighten the wheel mounting stud nuts in
proper sequence until all nuts are torqued to half
specification. Then repeat the tightening sequence to
the full specified torque of 135 N´m (100 ft. lbs.).
(6) Lower the vehicle.
FLUID
DIAGNOSIS AND TESTING - BRAKE FLUID
CONTAMINATION
Indications of fluid contamination are swollen or
deteriorated rubber parts.
Swollen rubber parts indicate the presence of
petroleum in the brake fluid.
To test for contamination, put a small amount of
drained brake fluid in clear glass jar. If fluid sepa-
rates into layers, there is mineral oil or other fluid
contamination of the brake fluid.
If brake fluid is contaminated, drain and thor-
oughly flush system. Replace master cylinder, propor-
tioning valve, caliper seals, wheel cylinder seals,
Antilock Brake hydraulic unit and all hydraulic fluid
hoses.
STANDARD PROCEDURE - BRAKE FLUID
LEVEL CHECKING
Check master cylinder reservoir fluid level a mini-
mum of twice annually.
Fluid reservoirs are marked with the words FULL
and ADD to indicate proper brake fluid fill level of
the master cylinder.
If necessary, add brake fluid to bring the level to
the bottom of the FULL mark on the side of the mas-
ter cylinder fluid reservoir.
Use only Mopartbrake fluid or equivalent from a
sealed container. Brake fluid must conform to DOT 3
specifications (DOT 4 or DOT 4+ are acceptable).
DO NOTuse brake fluid with a lower boiling
point, as brake failure could result during prolonged
hard braking.
Fig. 44 Guide Pins And Boots
1 - PINS
2 - BOOTS
5 - 32 BRAKES - BASERS
DISC BRAKE CALIPER GUIDE PINS (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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CAUTION: When replacing a master cylinder, be
sure to use the correct master cylinder for the type
of brake system the vehicle is equipped with.
The body of the master cylinder is an anodized alu-
minum casting. It has a machined bore to accept the
master cylinder pistons and threaded ports with
seats for the hydraulic brake line connections.
The brake fluid reservoir is mounted on the top of
the master cylinder. It is made of a see-through
polypropylene type plastic for easy fluid level view-
ing. A brake fluid level switch is attached to the
brake fluid reservoir.
The master cylinder is not a repairable component
and must be replaced if diagnosed to be functioning
improperly. The brake fluid reservoir and brake fluid
level switch can be replaced separately.
CAUTION: Do not hone the bore of the cylinder as
this will remove the anodized surface from the bore.
DESCRIPTION - RHD
The master cylinder used on right hand drive
(RHD) vehicles functions similarly to that used on
left hand drive (LHD) vehicles. The RHD master cyl-
inder, as well as the RHD power brake booster, is
located in the same area, but lower in the engine
compartment than LHD models (Fig. 47). For that
reason an extension manifold is placed between the
fluid reservoir and master cylinder housing allowing
the fluid reservoir to be positioned in the same loca-
tion as on LHD models.
OPERATION
When the brake pedal is depressed, the master cyl-
inder primary and secondary pistons apply brake
pressure through the chassis tubes to the brakes at
each tire and wheel assembly.
The master cylinder primary outlet port supplies
hydraulic pressure to the right front and left rear
brakes. The secondary outlet port supplies hydraulic
pressure to the left front and right rear brakes.
STANDARD PROCEDURE - MASTER CYLINDER
BLEEDING
CAUTION: When clamping master cylinder in vise,
only clamp master cylinder by its mounting flange.
Do not clamp master cylinder piston rod, reservoir,
seal or body.
(1) Clamp master cylinder in a vise.
NOTE: Use correct bleeder tubes when bleeding
master cylinder. Master cylinder outlet ports vary in
size and type depending on whether master cylin-
der is for a vehicle equipped with traction control or
not. Traction control equipped master cylinders
require the additional use of ISO style flare adapt-
ers supplied in Special Tool Package 8822 to be
used in conjunction with Bleeder Tubes, Special
Tool Package 8358.
(2) Attach special tools for bleeding master cylin-
der in the following fashion:
(a)For non-traction control equipped mas-
ter cylinders, thread a Bleeder Tube, Special Tool
8358±1, into each outlet port. Tighten each tube to
17 N´m (145 in. lbs.) torque. Flex bleeder tubes and
place open ends into mouth of fluid reservoir as far
down as possible (Fig. 48).
(b)For traction control equipped master
cylinders, thread one Adapter, Special Tool
8822±2, in each outlet port. Tighten Adapters to 17
N´m (145 in. lbs.) torque. Next, thread a Bleeder
Tube, Special Tool 8358±1, into each Adapter.
Tighten each tube to 17 N´m (145 in. lbs.) torque.
Flex bleeder tubes and place open ends into mouth
of fluid reservoir as far down as possible (Fig. 48).
NOTE: Make sure open ends of bleeder tubes stay
below surface of brake fluid once reservoir is filled
to proper level.
(3) Fill brake fluid reservoir with Mopartbrake
fluid or equivalent conforming to DOT 3 (DOT 4 and
DOT 4+ are acceptable) specifications. Make sure
fluid level is above tips of bleeder tubes in reservoir
to ensure no air is ingested during bleeding.
Fig. 47 RHD MASTER CYLINDER AND POWER
BRAKE BOOSTER
1 - POWER BRAKE BOOSTER
2 - BRAKE FLUID LEVEL SWITCH
3 - FLUID RESERVOIR
4 - MASTER CYLINDER
RSBRAKES - BASE5-35
MASTER CYLINDER (Continued)
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(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)
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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)
ProCarManuals.com

(7) Remove the screw fastening the proportioning
valve actuator rod bracket to the rear axle. Raise the
actuator lever to the full-upward position and hold it
there.
(8) With the aid of a helper, apply pressure to the
brake pedal until a pressure of 6895 kPa (1000 psi) is
obtained on the proportioning valve inlet gauge.
Then, based on the type of brake system the vehicle
is equipped with and the pressure specification
shown on the following table, compare the pressure
reading on the outlet gauge to the specification. If
outlet pressure at the proportioning valve is not
within specification when required inlet pressure is
obtained, replace the proportioning valve. (Refer to 5
- BRAKES/HYDRAULIC/MECHANICAL/PROPOR-
TIONING VALVE - REMOVAL)
CAUTION: Do not attempt to adjust the height sens-
ing proportioning valve. If found to be defective,
replace the valve.(9) Remove the pressure test fittings and pressure
gauges from the proportioning valve.
(10) Install the chassis brake lines in the correct
ports of the proportioning valve. Tighten all tube
nuts to 17 N´m (145 in. lbs.).
(11) If necessary, repeat the above steps on the
remaining side of the proportioning valve which con-
trol the other rear wheel brake.
(12) Attach the actuator lever and bracket to the
rear axle.
(13) Bleed rear brakes. (Refer to 5 - BRAKES -
STANDARD PROCEDURE)
(14) Road test vehicle.
PROPORTIONING VALVE SPECIFICATIONS
WHEEL
BASEDRIVE
TRAINSALES CODE BRAKE SYSTEMSPLIT
POINTSLOPEINLET
PRESSURE
PSIOUTLET
PRESSURE
PSI
SWB FWD BRB-BGF159DISC/DRUM
W/O ANTILOCKVAR. .59 1000 PSI 675-875 PSI
REMOVAL - PROPORTIONING VALVE (HEIGHT
SENSING)
(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 proportioning valve.
(2) Raise vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE).
CAUTION: Before removing the brake tubes from
the proportioning valve, the proportioning valve and
the brake tubes must be thoroughly cleaned. This is
required to prevent contamination from entering the
proportioning valve or the brake tubes.
(3) Remove the four brake tubes from the inlet and
outlet ports of the proportioning valve (Fig. 73).
(4) Remove the two bolts attaching the proportion-
ing valve and bracket to the vehicle (Fig. 73).
(5) Slide the bracket out from under rear track bar
bracket. Lower the valve down enough to pull its
actuator rod out of the axle bracket and remove the
proportioning valve from the vehicle.
Fig. 73 PROPORTIONING VALVE MOUNTING
1 - LEFT REAR OUTLET TUBE
2 - RIGHT REAR OUTLET TUBE
3 - RIGHT REAR INLET TUBE
4 - MOUNTING BOLTS
5 - LEFT REAR INLET TUBE
5 - 50 BRAKES - BASERS
PROPORTIONING VALVE (Continued)
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ROTOR RUNOUT
On-vehicle rotor runout is the combination of the
individual runout of the hub face and the runout of
the rotor. (The hub and rotor runouts are separable).
To measure rotor runout on the vehicle, first remove
the tire and wheel assembly. Reinstall the wheel
mounting nuts on the studs, tightening the rotor to
the hub. Mount the Dial Indicator, Special Tool
C-3339, with Mounting Adaptor, Special Tool SP-
1910 on steering arm. The dial indicator plunger
should contact braking surface of rotor approximately
ten millimeters from edge of rotor (Fig. 76). Check
lateral runout on both sides of the rotor, marking the
low and high spots on both. Runout limits can be
found in the specification table in this section. (Refer
to 5 - BRAKES/HYDRAULIC/MECHANICAL/RO-
TOR - SPECIFICATIONS)
If runout is in excess of the specification, check the
lateral runout of the hub face. Before removing the
rotor from the hub, place a chalk mark across both
the rotor and the one wheel stud closest to where the
high runout measurement was taken. This way, the
original mounting spot of the rotor on the hub is
indexed (Fig. 77).
Remove the rotor from the hub.
NOTE: Clean the hub face surface before checking
runout. This provides a clean surface to get an
accurate indicator reading.Mount Dial Indicator, Special Tool C-3339, and
Mounting Adaptor, Special Tool SP-1910, to the steer-
ing knuckle. Position the indicator stem so it contacts
the hub face near the outer diameter. Care must be
taken to position stem outside of the stud circle, but
inside of the chamfer on the hub rim (Fig. 78).
Hub runout should not exceed 0.03 mm (0.0012
inch). If runout exceeds this specification, the hub
must be replaced. (Refer to 2 - SUSPENSION/
FRONT/HUB / BEARING - REMOVAL)(Refer to 2 -
SUSPENSION/REAR/HUB / BEARING - REMOVAL)
If the hub runout does not exceed this specifica-
tion, install the rotor back on the hub, aligning the
chalk marks on the rotor with a wheel mounting
Fig. 75 Checking Rotor For Thickness
1 - CALIPER
Fig. 76 Checking Rotor Runout
1 - SPECIAL TOOL SP-1910
2 - 10 MILLIMETERS FROM EDGE
3 - DISC SURFACE
4 - SPECIAL TOOL C-3339
Fig. 77 Marking Rotor and Wheel Stud
1 - CHALK MARK
5 - 52 BRAKES - BASERS
ROTOR (Continued)
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