ISUZU TROOPER 1995 Workshop Manual

POWER STEERING SYSTEM TEST
TEST PROCEDURE
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 method used to
identify and
isolate hydraulic circuit difficulties. Prior
to performing this test, the following inspections and
corrections,
if necessary, must be made.
[!) INSPECT
• Pump reservoir for proper fluid level.
•
Pump belt for proper tension.
• 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 (Fig. 3B1-3).
The gage
must be between the shutoff valve and
pump.
Open the shutoff valve.
li5\l Tester: J-29877-A
~ Adapter: J-39213
3. Check the fluid level. Fill the reservoir with power
steering fluid, to the "Full" mark. Start the engine
and,
momentarily holding steering wheel against
stop, check the connections at tester
for leakage.
4. Bleed the system. Refer to "Bleeding the Power
Steering
System".
POWER STEERING GEAR AND PUMP 381-3
5. Start the engine and check the pump fluid level.
And power steering fluid if required. When the
engine is at
normal operating temperature,
increase engine speed to 1500 rpm.
U7 CAUTION:
VI Do not leave shutoff valve fully closed for more
than 5 seconds,
as the pump could become
damaged
internally.
6. Fully close the shutoff valve. Record the highest
pressures.
• If the pressure recorded is within 9300-9800
kPa (1350-1420 psi), the pump is functioning
within its specifications.
• If the pressure recorded is higher than 9800 kPa
(1420 psi), the valve in the pump is defective.
• If the pressure recorded is lower than 9300 kPa
(1350 psi), the valve or the rotating group in the
pump is defective.
7. If the pump checks 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 (or one) side
ofthe gear, the gear is leaking internally and must
be disassembled and repaired.
8. Shut the engine off, remove the testing gage,
reconnect the pressure hose, check the
fluid level
and make the needed repairs.
9. If the problem still exists, the steering and front
suspension must be thoroughly examined.
Shut off Valve
J-29877-A
Oil Pressure Gauge
J-29877-A
Fig. 3B1-3

381 - 4 POWER STEERING GEAR AND PUMP
ON-VEHICLE SERVICE
MAINTENANCE
The hydraulic system should be kept clean and fluid
level in the reservoir should be checked at regular
intervals
and fluid added when required. Refer to
"MAINTENANCE AND LUBRICATION" in section OB
ofthe manual for type offluid to be used and intervals
for filling.
If the system contains some dirt, flush it as detailed
later
in this section. If it is exceptionally dirty, both the
pump and the gear must be completely disassembled
before further usage.
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.
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 "MAINTENANCE AND LUBRI­
CATION" in Section OB 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 gear 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 power 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 power steering fluid as specified in
"MAINTENANCE AND LUBRICATION" in section OB.
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 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 and turn the steering wheel
slowly from lock to lock.
9. Stop the engine. Check the fluid level and refill
as required.
10.
If the fluid is extremely foamy, allow the vehicle
to stand a few minutes and repeat the above
procedure.
~ INSPECT
• Belt for tightness.
• Pulley for looseness or damage. The pulley
should not wobble with the engine running.
• Hoses so they are not touching any other parts
of the vehicle.
• Fluid level
and fill to the proper level.
FLUSHING THE POWER STEERING
SYSTEM
1. Raise 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 reservoir
with new power steering fluid. Turn the steering
wheel in both directions. DO NOT contact wheel
stops or hold the wheel in a corner, or fluid will
stop and the pump will be in pressure relief mode.
A sudden
overflow from the reservoir may
develop if the wheel is held at a stop.
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 power steering system components. Do not
re-use any drained power steering fluid.
~
~

STEERING WHEEL FREE PLAY ADJUST­
MENT
IL•I INSPECTION (Fig. 381-4)
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.
~~~~F-r-ee--pl-ay---m-m--(in_)_,j--o----3-0-(0----1-.1-8~)-
2. Also check the steering wheel for play and
looseness in mount by moving it back and forth
and sideways.
While driving, check for hard
steering, steering
shimmy and tendency to pull to
one side.
POWER STEERING GEAR AND PUMP 381-5
IEEI ADJUSTMENT (Fig. 381-5)
1. Align the front wheels properly in the straight
ahead position.
2. Loosen the lock nut on the adjusting screw of the
steering gear.
3. Turn the adjust screw clockwise to decrease free
play or counter-clockwise to incre~se.
4. After check of specified free play, t1ghten the lock
nut to specified torque.
~~~ Torque N·m (lb·ft) I 41 (30)
Fig. 381-5

381-6 POWER STEERING GEAR AND PUMP
STEERING GEAR
Removal steps 1. Pipe
2. Nut 3. Pitman arm
4. Coupling clamp bolt 5. Gear box mounting bolt and nut 6. Gear box
Installation steps To install, follow the removal steps in the reverse order.
Fig. 381-6
EJ REMOVAL
Preparation: • Remove the stone guard.
1. Pipe
2. Nut
• Remove the lower fan shroud.
Refer to
"Engine cooling" in section
681.
• Disconnect stabilizer bar at the
stabilizer links. Loosen stabilizer
bracket fixing nuts.
3. Pitman arm (Fig. 381-7)
1®1 Pitman arm remover: J-291 07
Fig. 381-7 4.
Coupling clamp bolt (Fig.
381-8)
• Make a setting mark across the coupling flange
and worm shaft to ensure reassembly of the
parts in the
original position.
Fig. 381-8
5. Gear box mounting bolt and nut
• Push the stabilizer bar aside and remove the
bolts and nuts (Fig. 381-9).
6. Gear box
..

lJ
Fig. 381-9
l••f INSTALLATION
6. Gear box (Fig. 381-1 0)
l£tj• Align the setting marks made at removal.
5. Gear box mounting bolt and nut
1~1 Torque N·m (lb·ft) 44 (33)
4. Coupling clamp bolt
~~~ Torque N·m (lb·ft) 25 (18)
3. Pitman arm (Fig. 381·11)
l£tj• Align the notched tooth.
2. Nut
~~~---T-o-rq_u_e __ N_·_m_(_lb-.ft-)~~---2-1_6_(1_5_9_) __ ___
1. Pipe
~~~--T-o-rq_u_e __ N--m----(-lb-.ft-)~-------4-4-(-33_) ____ _
POWER STEERING GEAR AND PUMP 381-7
Fig. 381-10
Fig. 381-11

381-8 POWER STEERING GEAR AND PUMP
POWER STEERING PUMP
<
4
Removal steps
1. Hose, suction
2. Hose,
flexible 3. Adjust bolt 4. Belt 5. Bolt 6. Pump assembly and pulley
7. Pulley
8. Adjust
plate
9. Pump assembly
Installation
steps To install, follow the removal steps in the reverse order.
Fig. 381-12
B REMOVAL
Preparation: • Place a drain pan below the pump.
1. Hose, suction
2. Hose, flexible
3. Adjust bolt
4. Belt
5.
6.
7.
8.
9.
Bolt
Pump assembly and pulley
Pulley
Adjust plate
Pump assembly
1•+1 INSTALLATION
9. Pump assembly
8. Adjust plate
~~~ Torque N·m (lb·ft) 56 (41)
7. Pulley
~~~ Torque N·m (lb·ft)
6. Pump assembly and pulley
5. Bolt
~~~ Torque N·m (lb·ft)
4.
3.
Belt
Adjust bolt
78 (58)
46 (34)
• After adjusting drive belt tension, tighten bolt
to specified torque.
I~I_T_o_rq....:...u_e_N_·_m_(_lb_·ft_)____! ___ 4_6...:..(3_4...:_) __ _
2. Hose, flexible
~~~ Torque N·m (lb·ft) 54 (40)
1. Hose, suction
• Fill and bleed the system. Refer to "Bleeding
the Power Steering System" in this section.

POWER STEERING GEAR AND PUMP 381-9
STEERING GEAR
1.,!,.1 DISASSEMBL V
W CAUTION:
UNIT REPAIR
Fig. 381-13
Yf Do not clamp the steering gear assembly in a vise
by the power cylinder housing.
1. Dust cover
2. Retaining ring
3. Back up ring
4. Oil seal
1) Clean the faces of the extended stub shaft.
2) Plug the hose fitting on the inlet side.
3) Remove the oil seal by blowing compressed
air through the
hole in the outlet side (Fig. 381-
14).
Disassembly steps
1. Dust cover
2. Retaining ring
3. Back up ring
4.
Oil seal 5. Lock nut 6. Top cover assembly
7. 0-ring
8. Sector shaft
9.
Ball-nut and valve housing
assembly
10. 0-ring
11. Seal ring
12. 0-ring
13. Gear
box
Reassembly steps
To reassemble, follow the
disassembly steps in the
reverse order.
Fig. 381-14

381-10 POWER STEERING GEAR AND PUMP
5. Lock nut
• Remove the adjusting screw lock nut and turn
the adjusting
screw counter-clockwise to
remove the preload between the sector gear
and the rack piston, then remove the
top cover
bolts.
6. Top cover assembly (Fig. 381-15)
• Holding the top cover stationary, turn the
adjusting screw
clockwise to raise and free to
cover, then remove the cover.
Fig. 381-15
7. 0-ring
8. Sector shaft (Fig. 381-16)
• Bring the stub shaft into straight-ahead
position. Do not force the sector shaft
off the
gear
box with a hammer or other impact tools.
9. Ball-nut and valve housing assembly (Fig. 381-
17)
• It is strongly advisable to always keep the ball
nut and valve housing assembly in a horizontal
position, or the rack piston will fall off onto the
end
of the worm, causing the rack piston to slip
out of the worm shaft and the balls to fall out.
10. 0-ring
11. Seal ring
12.
0-ring
13. Gear box
Fig. 381-16
Fig. 381-17
•

(1!] INSPECTION AND REPAIR
Inspect the following parts for wear, damage or any
other abnormal conditions.
• Bearing
• Ball-nut and valve housing
• Sector shaft
• Top cover
• Gear box
• Needle bearing
• Dust seal
• Seal ring
• Gasket
Ball-nut rotation (fig. 381-18)
Hold the ball nut and valve housing assembly vertically
and see
if the ball-nut lowers by turning smoothly. If
the ball-nut does not lower smoothly, check the worm
shaft for bending and foreign matter.
NOTE:
When testing the ball nut and valve housing assembly,
do not let it travel all the way to the end of worm shaft,
or damage to the ball tubes will result.
• Check sector shaft outside diameter (Fig. 381-
19).
~~~ Limit mm (in) 31.7 (1.25)
Fig. 3B1-18
Fig. 3B1-19
POWER STEERING GEAR AND PUMP 381-11
Seal ring setting (fig. 381-20)
8.
~·
Note the setting direction. Always install a
new part.
Apply a thin coat of power steering fluid to lip of
each part.
Dust seal setting (Fig. 381-20)
r=l • Note the setting direction. Always install a
1.=.1 new part.
l<=l()l • Apply a thin coat of power steering fluid to lip of
each part.
Dust seal
Fig. 3B1-20
Gasket setting (fig. 381-21)
1 .. 1• Note the setting direction.
a:;::::;::] • Apply a thin coat of power steering fluid to lip of
D each part.
Fig.
3B1-21

381 -12 POWER STEERING GEAR AND PUMP
l•!+l REASSEMBLY
13. Gear box
12.
0-ring (fig. 381-22)
r:::;:, • Apply a thin coat of power steering fluid.
D • Be sure to discard used part, and always use
new part for installation.
11. Seal ring (fig. 381-22)
r:::;:, • Apply a thin coat of power steering fluid.
D • Be sure to discard used part, and always use
new part for installation.
10.
0-ring (fig. 381-22)
r:::;:, • Apply a thin coat of power steering fluid.
D • Be sure to discard used part, and always use
new part for installation.
Seal ring
Fig. 3B1-22
9.
Ball-nut and valve housing assembly
1) It is strongly advisable to always keep the ball
screw and valve housing assembly in a
horizontal position (avoid holding it
vertically), or the rack piston will fall off onto
the end of the worm, causing the rack piston
to slip out of the worm shaft and ball to fall
out (Fig. 3B1-23).
2) Be careful not to drop the 0-ring into the
valve housing.
3) Tighten the valve housing retaining bolts to
the specified torque.
~~~ Torque N·m (lb.ft) I 47 (35)
8. Sector shaft
1) Tape the sector shaft serrations to protect the
seal ring from damage.
2) Align the center tooth of ball nut with that of
the sector shaft (Fig. 3B1-24). Fig.
3B1-23
Fig. 3B1-24
7. 0-ring
6. Top cover assembly
~~~ Torque N-m (lb·ftl I 47 (35)
5. Lock nut
r:cJ Adjust the backlash between the worm gear and
L:D the ball nut (Fig. 3B1-25).
1) With the worm gear rotating, set it to the
straight ahead position.
2) Set the worm shaft preload to below 1 Okg-cm
with the sector shaft adjusting screw.
3) Measure the worm shaft preload with the
worm gear turned 450° both to the right and
to the left.
The worm gear preload in these positions
should be 2-4kg-cm lower than in the straight
ahead position.
4) Lock the sector shaft adjusting screw with the
lock nut.
~~~ Lock nut torque N-m (lb·ft) I 41 (30)
•