2004 ISUZU TF SERIES steering wheel

POWER-ASSISTED STEERING SYSTEM 3B-7


Power Steering System Test
Test Procedure
F02RX002
Legend
(1) Bolt
(2) Hose
(3) Power Steering Unit
(4) Power Steering Pump


Test of fluid pressure in the power steering system is
performed to determine whether or not the oil pump and
power steering unit are functioning normally.
The power steering system test is used to identify and
isolate hydraulic circuit difficulties. Prior to performing
this test, the following inspections and corrections, i
f
necessary, must be made.


Inspect pump reservoir for proper fluid level.


Inspect pump belt for proper tension.


Inspect pump driver pulley condition.
1. Place a container under the pump to catch the fluid
when disconnecting or connecting the hoses.
2.
With the engine NOT running, disconnect the
pressure hose at the power steering pump and
install power steering tester 5-8840-0135-0 as
shown in the illustration. The gage must be between
the shutoff valve and pump. Open the shutoff valve.
3. Check the fluid level. Fill the reservoir with powe
r
steering fluid, to the "Full" mark. Start the engine,
then turn the steering wheel and momentarily hold it
against a stop (right or left). Turn the engine off and
check the connections at tester for leakage.
4. Bleed the system. Refer to Bleeding the Powe
r
Steering System in this section.
5. Start the engine and check the fluid level. Add
power steering fluid if required. When the engine is
at normal operating temperature, increase engine
speed to 1500 rpm.
CAUTION: Do not leave shutoff valve fully closed
for more than 5 seconds, as the pump could
become damaged internally.

3B-8 POWER-ASSISTED STEERING SYSTEM

6. Fully close the shutoff valve. Record the highest
pressures.


If the pressure recorded is within 9300-9800 kPa
(95-100 kg/cm
2/1350-1420 psi), the pump is
functioning within its specifications.


If the pressure recorded is higher than 9800 kPa
(100 kg/cm
2/1420 psi), the valve in the pump is
defective.


If the pressure recorded is lower than 9300 kPa (95
kg/cm
2/1350 psi), the valve or the rotating group in
the pump is defective.
7. If the pump pressures are within specifications,
leave the valve open and turn (or have someone
else turn) the steering wheel fully in both directions.
Record the highest pressures and compare with the
maximum pump pressure recorded in step 6. If this
pressure cannot be built in either side of the powe
r
steering unit, the power steering unit is leaking
internally and must be replaced.
8. Shut the engine off, remove the testing gauge.
9. Reconnect the pressure hose, check the fluid level
and make the needed repairs.
10. If the problem still exists, the steering and fron
t
suspension must be thoroughly examined.

Maintenance
The hydraulic system should be kept clean and fluid
level in the reservoir should be checked at regula
r
intervals and fluid added when required. Refer to
Recommended Fluids and Lubricants in General
Information section for the type of fluid to be used and
the intervals for filling.
If the system contains some dirt, flush it as described in
this section. If it is exceptionally dirty, the pump must be
completely disassembled before further usage. (The
steering unit cannot be disassembled.)
All tubes, hoses, and fittings should be inspected for
leakage at regular intervals. Fittings must be tight. Make
sure the clips, clamps and supporting tubes and hoses
are in place and properly secured.
Power steering hoses and lines must not be twisted,
kinked or tightly bent. Air in the system will cause
spongy action and noisy operation. When a hose is
disconnected or when fluid is lost, for any reason, the
system must be bled after refilling. Refer to Bleeding the
Power Steering System in this section.


Inspect belt for tightness.


Inspect pulley for looseness or damage. The pulle
y
should not wobble with the engine running.


Inspect hoses so they are not touching any othe
r
parts of the vehicle.


Inspect fluid level and fill to the proper level.

Fluid Level
1. Run the engine until the power steering fluid
reaches normal operating temperature, about 55
C (130
F), then shut the engine off.
2. Check the level of fluid in the reservoir.
3. If the fluid level is low, add power steering fluid as
specified in General Information to the proper level
and install the receiver cap.
4. When checking the fluid level after the steering
system has been serviced, air must be bled from
the system. Refer to Bleeding the Power Steering
System in this section.

Bleeding The Power Steering System
When a power steering pump or unit has been installed,
or an oil line has been disconnected, the air that has
entered the system must be bled out before the vehicle
is operated. If air is allowed to remain in the powe
r
steering fluid system, noisy and unsatisfactory operation
of the system may result.

Bleeding Procedure
When bleeding the system, and any time fluid is added
to the power steering system, be sure to use only powe
r
steering fluid as specified in General Information.
1. Fill the pump fluid reservoir to the proper level and
let the fluid settle for at least two minutes.
2. Start the engine and let it run for a few seconds. Do
not turn the steering wheel. Then turn the engine
off.
3. Add fluid if necessary.
4. Repeat the above procedure until the fluid level
remains constant after running the engine.
5. Raise and support the front end of the vehicle so
that the wheels are off the ground.
6. Start the engine. Slowly turn the steering wheel right
and left, lightly contacting the wheel stops.
7. Add power steering fluid if necessary.
8. Lower the vehicle, set the steering wheel at the
straight forward position after turning it to its full
steer positions 2 or 3 times, and stop the engine.
9. Check the fluid level and refill as required.
10. If the fluid is extremely foamy, allow the vehicle to
set a few minutes, then repeat the above procedure.

Flushing The Power Steering System
1. Raise and support the front end of the vehicle off
the ground until the wheels are free to turn.
2. Remove the fluid return line at the pump inlet
connector and plug the connector port on the pump.
Position the line toward a large container to catch
the draining fluid.
3. While running the engine at idle, fill the reservoi
r
with new power steering fluid. Turn the steering
wheel in both directions. Do not contact or hold the
steering wheel to the wheel stops. This will cause
the pump to go to pressure relief mode, which ma
y
cause a sudden fluid overflow at the reservoir.

POWER-ASSISTED STEERING SYSTEM 3B-9

4. Install all the lines and hoses. Fill the system with
new power steering fluid and bleed the system as
described in Bleeding The Power Steering System.
Operate the engine for about 15 minutes.
Remove the pump return line at the pump inlet and
plug the connection on the pump. While refilling the
reservoir, check the draining fluid for contamination.
If foreign material is still evident, replace all lines,
disassemble and clean or replace the powe
r
steering system components. Do not re-use any
drained power steering fluid.

Steering Wheel Free Play Inspection
060R300016
1. With the tires in the straight-ahead position, check
the amount of steering wheel play by turning the
wheel in both directions until the tires begin to move.
NOTE: The wheel free play should be checked with the
engine running.
Free play: 0 - 30 mm (0 - 1.18 in)
2.
Also check the steering wheel for play and
looseness in the mount by moving it back and forth
and sideways. When test driving, check for hard
steering, steering shimmy and tendency to pull to
one side.

Front End Alignment Inspection and
Adjustment
Toe-in Adjustment
Toe-in: Refer to Section 3A FRONT ALIGNMENT
1. To adjust the toe-in angle, loosen the lock nuts (2)
on the tie rod (1) and turn the tie rod. Turn both rods
the same amount, to keep the steering wheel
centered .
This illustration is based on the RHD model.
431R30006
2. Tighten the lock nut to the specified torque.
Torque:
92 - 104 N




m (9.4 - 10.6 kg




m/68 - 77 lb ft)

3B-24 POWER-ASSISTED STEERING SYSTEM

Side Plate
The sliding faces of parts must be free from step wear
(more than 0.01 mm), which can be felt by the finger
nail. The parts with minor scores may be reused after
lapping the face.

Valve
The sliding face of the valve must be free from burrs
and damage. The parts with minor scores may be
reused after smoothing with emery cloth (#800 or finer).

Shaft
Oil seal sliding faces must be free from a step wear
which can be felt by the finger nail. Needle bearing fitting
face must be free from damage and wear.

O-ring, Oil Seal, Retaining Ring
Be sure to discard used parts, and always use new
parts for installation. Prior to installation, lubricate all
seals and rings with power steering fluid.

Pressure Switch
Check the switch operation as follows:
With engine idling and A/C on, turn the steering wheel
fully to the left; compressor should interrupt and engine
idle speed will increase. Shut off A/C and again turn
steering fully to the left; engine idle will increase. I
f
system fails to function properly, disconnect connector
at the pressure switch and repeat system check while
testing continuity across disconnected SW connector.

Reassembly
1. Install oil seal to front housing. Be sure to discard
used oil seal, and always use new parts fo
r
installation.
CAUTION: When installing the oil seal, be careful
not to damage the oil seal contacting surface of the
housing.
2. Install shaft assembly.
3. Install the vanes to roter with curved face in contact
with the inner wall of cam.
442RS005
4. Install rotor and vanes to cam.
5. Install pin to front housing.
6. Install two new O-rings to front housing. Be sure to
discard used O-ring.
7. Install side plate.
CAUTION: When installing side plate, be careful not
to damage its inner surface. Damaged side plate
may cause poor pump performance, pump seizure
or oil leakage.
8. Install pump cartridge assembly to front housing.
9. Install snap ring to shaft end.
10. Install rear housing with a new O-ring. Be sure to
discard used O-ring. Then install bolt and tighten it
to specified torque.
Torque: 22-26 N




m (2.2-2.7 kg




m/16-20 lb ft)
11. Install suction pipe with a new O-ring. Be sure to
discard used O-ring. Then install bolt and tighten it
to specified torque.
Torque: 7.8-12 N




m (0.8-1.2 kg




m/6-9 lb ft)
12. Install relief valve and spring.
13. Install connector with a new O-ring. Be sure to
discard used O-ring. Tighten the connector to
specified torque.
Torque: 49-69 N




m (5.0-7.0 kg




m/36-51 lb ft)
14. Install pressure switch assembly and tighten it to
specified torque.
Torque: 15-20 N




m (1.5-2.0 kg




m/11-14 lb ft)

3B-28 POWER-ASSISTED STEERING SYSTEM

Inspection and Repair
Make all necessary adjustments, repairs, and part
replacements if wear, damage, or other problems are
discovered during inspection.

Rotor
442RS002
Check that the groove in the vane is free from excessive
wear and that the vane slides smoothly. When par
t
replacement becomes necessary, the pump cartridge
should be replaced as a subassembly.

Vane
442RS003
Sliding faces of the vane should be free from wear.
(Particularly the curved face at the tip that contact with
the cam should be free from wear and distortion). When
part replacement becomes necessary, the pump
cartridge should be replaced as a subassembly.

Cam
The inner face of the arm should have a uniform contact
pattern without a sign of step wear. When part
replacement becomes necessary, the pump cartridge
should be replaced as a subassembly.

Side Plate
The sliding faces of parts must be free from step wear
(more than 0.01 mm), which can be felt by the finge
r
nail.
The parts with minor scores may be reused after lapping
the face.

Relief Valve
The sliding face of the valve must be free from burrs
and damage. The parts with minor scores may be
reused after smoothing with emery cloth (#800 or finer).

Shaft
Oil seal sliding faces must be free from a step wear
which can be felt by the finger nail. Bushing fitting face
must be free from damage and wear.

O-ring, Oil Seal, Snap Ring
Be sure to discard used parts, and always use new
parts for installation. Prior to installation, lubricate all
seals and rings with power steering fluid.

Pressure Switch
Check the switch operation as follows:
With engine idling and A/C on, turn the steering wheel
fully to the left; compressor should interrupt and engine
idle speed will increase. Shut off A/C and again turn
steering fully to the left; engine idle will increase. I
f
system fails to function properly, disconnect connecto
r
at the pressure switch and repeat system check while
testing continuity across disconnected SW connector.

Reassembly
1. Install oil seal to front housing. Be sure to discard
used oil seal, and always use new parts fo
r
installation.
CAUTION: When installing the oil seal, be careful
not to damage the oil seal contacting surface of the
housing.
2. Install shaft assembly.

POWER-ASSISTED STEERING SYSTEM 3B-31

Supplemental Restraint System Steering Wheel & Column
Service Precaution
This steering wheel and column repair section covers
the Supplemental Restraint System (SRS) steering
column. The following repair procedures are specific to
SRS components. When servicing a vehicle equipped
with Supplemental Restraint System, pay close attention
to all WARNINGS and CAUTIONS.
For detailed explanation about SRS, refer to Restraints
section.
WARNING: THIS VEHICLE HAS A SUPPLEMENTAL
RESTRAINT SYSTEM (SRS). REFER TO THE SRS
COMPONENT AND WIRING LOCATION VIEW IN
ORDER TO DETERMINE WHETHER YOU ARE
PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING. WHEN YOU
ARE PERFORMING SERVICE ON OR NEAR THE
SRS COMPONENTS OR THE SRS WIRING, REFE
R
TO THE SRS SERVICE INFORMATION. FAILURE TO
FOLLOW WARNINGS COULD RESULT IN POSSIBLE
AIR BAG DEPLOYMENT, PERSONAL INJURY, O
R
OTHERWISE UNNEEDED SRS SYSTEM REPAIRS.
SAFE HANDLING OF INFLATOR MODULES
REQUIRES FOLLOWING THE PROCEDURES
DESCRIBED BELOW FOR BOTH LIVE AND
DEPLOYED MODULES.
SAFETY PRECAUTIONS MUST BE FOLLOWED
WHEN HANDLING A DEPLOYED AIR BAG
ASSEMBLY (AIR BAG). AFTER DEPLOYMENT, THE
AIR BAG ASSEMBLY (AIR BAG) SURFACE MAY
CONTAIN A SMALL AMOUNT OF SODIUM
HYDROXIDE, A BY-PRODUCT OF THE
DEPLOYMENT REACTION, THAT IS IRRITATING TO
THE SKIN AND EYES. MOST OF THE POWDER ON
THE AIR BAG ASSEMBLY (AIR BAG) IS HARMLESS.
AS A PRECAUTION, WEAR GLOVES AND SAFETY
GLASSES WHEN HANDLING A DEPLOYED AIR BAG
ASSEMBLY, AND WASH YOUR HANDS WITH MILD
SOAP AND WATER AFTERWARDS.

WHEN CARRYING A LIVE AIR BAG ASSEMBLY,
MAKE SURE THE BAG AND TRIM COVER ARE
POINTED AWAY FROM YOU. NEVER CARRY AN AI
R
BAG ASSEMBLY BY THE WIRES OR CONNECTO
R
ON THE UNDERSIDE OF MODULE. IN THE CASE OF
AN ACCIDENTAL DEPLOYMENT, THE BAG WILL
THEN DEPLOY WITH MINIMAL CHANCE OF INJURY.
WHEN PLACING A LIVE AIR BAG ASSEMBLY ON A
BENCH OR OTHER SURFACE, ALWAYS FACE THE
BAG AND TRIM COVER UP, AWAY FROM THE
SURFACE.
NEVER REST A STEERING COLUMN ASSEMBLY
ON THE STEERING WHEEL WITH THE AIR BAG
ASSEMBLY FACE DOWN AND COLUMN VERTICAL.
THIS IS NECESSARY SO THAT A FREE SPACE IS
PROVIDED TO ALLOW THE AIR BAG ASSEMBLY
TO EXPAND IN THE UNLIKELY EVENT OF
ACCIDENTAL DEPLOYMENT. OTHERWISE,
PERSONAL INJURY COULD RESULT.
TO AVOID DEPLOYMENT WHEN
TROUBLESHOOTING THE SRS SYSTEM, DO NOT
USE ELECTRICAL TEST EQUIPMENT, SUCH AS
BATTERY-POWERED OR A/C-POWERED VOLT-
METER, OHMMETER, ETC., OR ANY TYPE OF
ELECTRICAL EQUIPMENT OTHER THAN SPECIFIED
IN THIS MANUAL. DO NOT USE A NON-POWERED
PROBE-TYPE TESTER.
INSTRUCTIONS IN THIS MANUAL MUST BE
FOLLOWED CAREFULLY, OTHERWISE PERSONAL
INJURY MAY RESULT.

SRS Connectors
CAUTION: The special yellow color connectors are
used for supplemental restraint system-air bag
circuit.
When removing the cable harness, do not pull the
cables. Otherwise, cable disconnection may occur.
When connect the SRS connector, insert the
connector completely. Imperfect locking may cause
malfunction of SRS circuit.

3B-32 POWER-ASSISTED STEERING SYSTEM

Inflator Module
Inflator Module and Associated Parts
430R300013

Legend
(1) Horn Lead
(2) SRS Connector
(3) Steering Wheel
(4) Steering Wheel Fixing Nut
(5) Inflator Module or Horn Pad

POWER-ASSISTED STEERING SYSTEM 3B-33

Removal
1. Turn the steering wheel so that the vehicle's wheels
are pointing straight ahead.
2. Turn the ignition switch to "LOCK".
3. Disconnect the battery "-" terminal cable, and wait a
t
least 5 minutes. (with SRS air bag)
4. Disconnect the yellow 2-way SRS connector located
under the steering column. (with SRS air bag)
CAUTION: The wheels of the vehicle must be
straight ahead and the steering column in the
"LOCK" position before disconnecting the steering
wheel. Failure to do so will cause the coil assembly
to become uncentered which will cause damage to
the coil assembly. (with SRS air bag)
5. Disable the SRS (Refer to "Disabling the SRS" in
this section). (with SRS air bag)
6. Check the both side hole of the steering cover. (with
SRS air bag)
060R300025


7. Check the position of the pins in a hole. Push the
pin in the direction of an arrow. (with SRS air bag)
060R300032
8. Push the four pins at 
5
6 mm bar. (with SRS air
bag)
060R300031
9. Cancel the lock four pins. (with SRS air bag)