power steering ISUZU TF SERIES 2004 Repair Manual

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-10 POWER-ASSISTED STEERING SYSTEM

Torque Specification
N
m (kg
m/Ib
ft)

This illustration is based on the RHD model. RTW33BLF000101

Special Tools

ILLUSTRATION

TOOL NO.
TOOL NAME
ILLUSTRATION


TOOL NO.
TOOL NAME



5-8840-0135-0
Tester;
Power steering


5-8840-2297-0
Adapter;
Power steering tester

POWER-ASSISTED STEERING SYSTEM 3B-11

Power Steering Unit
Power Steering Unit and Associated Parts

This illustration is based on the RHD model. 431R300016
Legend
(1) Crossmember
(2) Power Steering Unit Assembly
(3) Bracket
(4) Universal joint (Steering shaft)


Removal
1. Remove the universal joint assembly.
Make a setting mark across the coupling flange and
steering unit to ensure reassembly of the parts in
the original position.
2. Drain power steering fluid.

3. Remove the tie rod end assembly from knuckle.
Use tie rod end remover 5-8840-2005-0.

3B-12 POWER-ASSISTED STEERING SYSTEM

901RW270
4. Disconnect the feed line and return line from
steering unit.
Remove the clips on the crossmember and frame.
Wire the power steering line to frame.
NOTE: Take care to prevent foreign matter from entr
y
when disconnect the power steering line.
5. Remove the power steering unit from the
crossmember.


Installation
1. Install power steering unit to crossmember.
Tighten fixing bolt and nut to specified torque.
Torque:
106 – 126 N




m (10.8 – 12.8 kg




m/78 - 93 lb ft)
Torque:
198 - 242 N




m (20.2 – 24.7 kg




m/146 - 178 lb ft)
2. Connect the feed line and return line.
Torque:
20 - 29 N





m (2.0 – 3.0 kg





m/14 - 22 lb ft)
3. Install tie-rod end assembly to knuckle.
Torque:
88 – 127 N




m (9.0 – 13.0 kg




m/65 - 94 lb ft)
4.
Align the setting marks on the universal joint
(applied at disassembly) with the setting marks on
the power steering unit. Connect the universal joint
assembly to the power steering unit. Temporaril
y
tighten the universal joint bolts on the universal joint
assembly side.
5. Tighten the universal joint bolts (bolts at either end
of the joint temporarily tightened in Step 1 and 2) to
the specified torque.
6. Install the stone guard.
7. Bleed the system.
Refer to Bleeding the Power Steering System in this
section.

POWER-ASSISTED STEERING SYSTEM 3B-13

Power Steering Unit Disassembled View

This illustration is based on the RHD model. 440R300003
Legend
(1) Tie-rod End
(2) Lock Nut
(3) Clip
(4) Bellows
(5) Band
(6) Tie-rod Assembly
(7) Oil Line
(8) Inner Ball Joint Assembly
(9) Tab Washer
(10) Mounting Rubber
(11) Housing Assembly



Disassembly
NOTE: The valve housing is made of aluminum and
care should be exercised when clamping in a vise, etc.
to prevent distortion or damage.
1. Loosen lock nut and remove tie-rod end.
2. Remove clip and band, then remove bellows.
3. Remove tie-rod assembly.
To remove, move the boot toward the tie-rod end,
then remove tab washer.
4. Remove oil line, mounting rubber and dust cover.
Inspection and Repair
Inspect the following parts for wear, damage or any
abnormal conditions.

3B-14 POWER-ASSISTED STEERING SYSTEM


Tie-rod End
If looseness or play is found when checked by moving
the end of ball joint at tie-rod end, replace tie-rod end.

Tie-rod Assembly
If the resistance is insufficient or play is felt when
checked by moving the ball on the tie-rod, replace the
tie-rod assembly.

Rubber Parts
If wear or damage is found through inspection, replace
with new ones.

Reassembly
1. Install mounting rubber and dust cover (If removed).
2. Install oil line.
Torque: 10 - 15 N




m (1.0 – 1.5 kg




m/87 - 130 lb in)
3. Install tie-rod assembly with tab washer.
Apply grease to ball joint, install tie-rod and tab
washer, then tighten to specified torque.
Torque: 69 - 98 N




m (7.0 – 10.0 kg




m/51 - 72 lb ft)
After tightening, bend tab washer against width
across flat of inner ball joint.
4.
Apply a thin coat of grease to the shaft for smooth
installation. Then install bellows.
5. Install band and clip.
6. Install tie-rod end and tighten lock nut.
Torque:
92 - 104 N




m (9.4 – 10.6 kg




m/68 - 77 lb ft)

Main Data and Specifications
General Specifications
2WD 4WD
Power steering Without With
Type Rack and pinion
Rack stroke mm (in) 138 (5.43) 138 (5.43) 152 (5.98)
Steering unit
Lock to lock 4.84 3.38 3.26

POWER-ASSISTED STEERING SYSTEM 3B-15

Torque Specifications
N
m (kg
m/Ib
ft)

This illustration is based on the RHD model. RTW33LF000201

Special Tools

ILLUSTRATION

TOOL NO.
TOOL NAME



5-8840-2005-0
(J-29107)
Tie rod end remover

3B-16 POWER-ASSISTED STEERING SYSTEM

Power Steering Pump
Power Steering Pump and Associated Parts (4JH1-TC, 4JA1-TC, 4JA1-L)
442R300002
Legend
(1) Pump Assembly
(2) Hose, Suction
(3) Hose, Flexible
(4) Bolt


Removal
1. Remove the drive belt.
2. Remove the pulley
3. Place a drain pan below the pump.
4. Disconnect the suction hose.
5. Disconnect the flexible hose.
6. Remove the power steering fixing bolt and remove
the pump assembly.

Installation
1. Install the pump assembly to the pump braket,
tighten the fixing bolt to the specified torque.
Torque: 34 - 46 N·m (3.5 – 4.7 kg·m/25 - 34 lb ft)
2. Install the flexible hose.
Tighten the eye bolt to specified torque.
Torque: 49 - 59 N·m (5.0 – 6.0 kg·m/36 - 43 lb ft)
3. Install the pulley and tighten the bolt to the specified
torque.
Torque: 26 - 30 N·m (2.7 –3.1 kg·m/20 - 22 lb ft)

4. Install the drive belt.
5. Connect the suction hose, then fill and bleed system.
Refer to Bleeding the Power Steering System in this
section.