engine coolant CHRYSLER VOYAGER 2004 User Guide

Kilometers 149 000 154 000 158 000 160 000 163 000 168 000
(Miles) (93,000) (96,000) (99,000) (100,000) (102,000) (105,000)
Change engine oil and engine
oil filter.XXX X X
Inspect the brake linings. X
Inspect the engine air cleaner
filter, replace if necessary. *XXXXX
Replace theengine air
cleaner filter*X
Inspect and adjust the power
steering pump belt tension on
2.4 liter engines.X
Inspect the generator belt on
2.4 liter engines, replace if
necessary.X
Inspect engine accessory
drive belts on 3.3 liter
engines, replace if necessary.
³X
Change the manual
transmission fluid.X
Change the All Wheel Drive
(AWD) power transfer unit,
overrunning clutch and rear
carrier fluid. (See note at the
end of this chart)X
Flush and replace the engine
coolant at 60 months or
100,000 miles.X
Replace the air conditioning
filter.X
0 - 22 LUBRICATION & MAINTENANCERS
MAINTENANCE SCHEDULES (Continued)

DESCRIPTION ± DIESEL ENGINES ± EXPORT
There are two maintenance schedules that show
therequiredservice for your vehicle.
First is ScheduleªAº. It is for vehicles that are not
operated under any of the conditions listed under
Schedule9B9.
Second is ScheduleªBº. It is for vehicles that are
operated under the conditions that are listed below
and at the beginning of the schedule.
²Extensive engine idling.
²Driving in dusty conditions.
²More than 50% of your driving is at sustained
high speeds during hot weather, above 32É C (90É F).
²Trailer towing.
²Taxi, police, or delivery service (commercial ser-
vice).
NOTE: Most vehicles are operated under the condi-
tions listed for Schedule(B(.
Use the schedule that best describes your driving
conditions. Where time and mileage are listed, follow
the interval that occurs first.
CAUTION: Failure to perform the required mainte-
nance items may result in damage to the vehicle.
At Each Stop for Fuel
²Check the engine oil level about 5 minutes after
a fully warmed engine is shut off. Checking the oil
level while the vehicle is on level ground willimprove the accuracy of the oil level reading. Add oil
only when the level is at or below the ADD or MIN
mark.
²Check the windshield washer solvent and add if
required.
Once a Month
²Check the tire pressure and look for unusual
wear or damage.
²Inspect the battery and clean and tighten the
terminals as required.
²Check the fluid levels of coolant deaeration bot-
tle, brake master cylinder and transmission, add as
needed.
²Check all lights and all other electrical items for
correct operation.
At Each Oil Change
²Change the engine oil filter.
²Inspect the exhaust system.
²Inspect the brake hoses.
²Inspect the CV joints and front suspension com-
ponents.
²Check the manual transmission fluid level.
²Check the coolant level, hoses, and clamps.
²Inspect engine accessory drive belts. Replace as
necessary.
²Inspect for the presence of water in the fuel fil-
ter/water separator unit.
²Rotate the tires at each oil change interval (20
000 km).
SCHEDULE A - DIESEL ENGINES
Kilometers 20 000 km 40 000 km 60 000 km 80 000 km 100 000
km
Change engine oil and engine oil filter.XXXX X
Inspect engine air filter element. Replace as
necessary.XX X
Replace engine air filter element X X
Replace fuel filter/water separator unit.XXXX X
Inspect timing belt tensioner and replace if
necessary. ³X
Replace engine timing belt and idler
pulleys.X
Check front end alignment. X X
Inspect the tie rod ends and boot seals. X X
Inspect the brake linings.XXXX X
0 - 24 LUBRICATION & MAINTENANCERS
MAINTENANCE SCHEDULES (Continued)

Kilometers 120 000
km140 000
km160 000
km180 000
km
Change engine oil and engine oil filter. X X X X
Inspect engine air filter element. Replace as necessary. X X
Inspect accessory drive belts and replace if necessary. X
Replace engine air filter element X X
Replace fuel filter/water separator unit. X X X X
Flush and replace engine coolant. X
Check front end alignment. X X
Inspect the tie rod ends and boot seals. X X
Inspect the brake linings. X X X X
Inspection and service should also be performed
anytime a malfunction is observed or suspected.
Retain all receipts.³ Replace if there is superficial wear, bearing clear-
ance, or evident grease leakage.
SCHEDULE B - DIESEL ENGINES
Follow schedule ªBº if you usually operate your
vehicle under one or more of the following conditions.
²Extensive engine idling.
²Driving in dusty conditions.²More than 50% of your driving is at sustained
high speeds during hot weather, above 32É C (90É F).
²Trailer towing.
²Taxi, police, or delivery service (commercial ser-
vice).
Kilometers 10 000 km 20 000 km 30 000 km 40 000 km 50 000 km
Change engine oil and engine oil filter.XXXX X
Inspect engine air filter element. Replace as
necessary.XX X
Replace engine air filter element X X
Replace fuel filter/water separator unit. X X
Check front end alignment. X X
Change the manual transaxle fluid. X
Inspect the tie rod ends and boot seals. X
Inspect the brake linings.XXXX X
RSLUBRICATION & MAINTENANCE0-25
MAINTENANCE SCHEDULES (Continued)

Kilometers 60 000
km70 000 km 80 000 km 90 000 km 100 000
km
Change engine oil and engine oil filter. X X X X X
Inspect engine air filter element. Replace as
necessary.XX
Replace engine air filter element X X X
Replace fuel filter/water separator unit. X X X
Inspect timing belt tensioner and replace if
necessary. ³X
Replace engine timing belt and idler pulleys. X
Check front end alignment. X X
Change the manual transaxle fluid. X X
Inspect the tie rod ends and boot seals. X
Inspect the brake linings. X X X X X
Kilometers 110 000
km120 000
km130 000
km140 000
km150 000
km160 000
km
Change engine oil and engine
oil filter.XXXXX X
Inspect engine air filter
element. Replace as
necessary.XXX
Inspect accessory drive belts
and replace if necessary.X
Replace engine air filter
elementXX X
Replace fuel filter/water
separator unit.XX X
Flush and replace engine
coolant.X
Check front end alignment. X X X
Inspect the tie rod ends and
boot seals.XX
Inspect the brake linings. XXXXX X
Inspection and service should also be performed
anytime a malfunction is observed or suspected.
Retain all receipts.
³ Replace if there is superficial wear, bearing clear-
ance, or evident grease leakage.WARNING: You can be badly injured working on or
around a motor vehicle. Do only that service work
for which you have the knowledge and the right
equipment. If you have any doubt about your ability
to perform a service job, take your vehicle to a
competent mechanic.
0 - 26 LUBRICATION & MAINTENANCERS
MAINTENANCE SCHEDULES (Continued)

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)

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)

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

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

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

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