1998 NISSAN PICK-UP Repair Manual

Description
CAUTION:
lParts which can be disassembled are strictly limited.
Never disassemble parts other than those specified.
lDisassemble in as clean a place as possible.
lClean your hands before disassembly.
lDo not use rags; use nylon cloths or paper towels.
lFollow the procedures and cautions indicated in the Ser-
vice Manual.
SST810C
POWER STEERING SYSTEM (Model: PB59K)
ST-27

Removal and Installation
Before removal, clean gear housing and oil pump exteriors
using a steam cleaner. Then dry with compressed air.
STEERING GEAR
Power Steering Gear Component
SST123CB
SST733C
POWER STEERING GEAR (Model: PB59K)
ST-28

Pre-disassembly Inspection and Adjustment
Before disassembling power steering gear component
parts, make sure there is no oil leakage around sealing por-
tion and check steering turning torque as follows:
Check sealing portion.
lSector shaft cover O-ring
lSector shaft U-packing
lSector shaft oil seal
lRear housing O-ring
lGear housing O-ring
Discard any oil seal and O-ring which have been removed.
Replace oil seal and O-ring if sealing surface is deformed or
cracked.
TURNING TORQUE MEASUREMENT
1. Measure turning torque at 360É position.
a. Install steering gear on Tool.
b. Turn stub shaft all the way to right and left several times.
c. Measure turning torque at 360É position from straight-ahead
position with Tools.
Turning torque at 360É:
0.15 - 0.78 N´m (1.5 - 8.0 kg-cm, 1.3 - 6.9 in-lb)
d. Measure turning torque at straight-ahead position.
Straight-ahead position is a position where stub shaft is
turned 2.14 turns (two full turns and 50É) from lock position.
Turning torque at straight-ahead position:
0.2 - 0.5 N´m (2 - 5 kg-cm, 1.7 - 4.3 in-lb)
higher than turning torque at 360É
Maximum turning torque:
0.44 - 1.18 N´m (4.5 - 12 kg-cm, 3.9 - 10.4 in-lb)
If turning torque is not within specifications, adjust by turn-
ing sector shaft adjusting screw.
SST040-A
SST652AA
SST653A
POWER STEERING GEAR (Model: PB59K)
ST-29

2. Tighten adjusting screw lock nut with tools.
Disassembly
Before disassembly, measure turning torque.
If not within specifications, replace steering gear assembly.
CAUTION:
Oil sealing parts and snap ring must not be used again after
removal.
1. Place steering gear in a vise with Tool.
2. Set worm gear in a straight-ahead position.
3. Loosen (do not remove) sector shaft cover bolt.
4. Knock out end of sector shaft with a plastic hammer.
5. Remove sector shaft by hand.
6. Remove oil seal.
7. Remove U-packing.
CAUTION:
When removing oil seal and U-packing, be careful not to
scratch gear housing.
SST654A
SST040-A
SST319C
SST320CA
POWER STEERING GEAR (Model: PB59K)
Pre-disassembly Inspection and Adjustment
(Cont'd)
ST-30

8. Remove lock nut, then loosen adjusting screw using a screw-
driver. Separate sector cover and sector shaft.
9. Remove O-ring.
10. Remove U-packing.
CAUTION:
lWhen removing U-packing, be careful not to scratch sec-
tor cover, needle bearing, etc.
lNeedle bearing cannot be disassembled. If it is
damaged, remove sector cover assembly.
11. Remove dust seal.
12. Remove rear housing bolts.
13. Remove rear housing together with worm gear assembly.
CAUTION:
Worm gear assembly cannot be disassembled. When it is
removed, be careful not to disengage worm gear from shaft
or allow it to drop.
14. Remove teflon ring and O-ring of worm gear assembly.
Assembly
1. Install new O-ring on worm gear assembly.
lApply a thin coat of ATF to new O-ring.
2. Install new teflon ring on worm gear assembly.
lMake sure that teflon ring is seated in correct position.
3. Install new O-rings into rear housing.
SST321C
SST322C
SST323C
SST738C
POWER STEERING GEAR (Model: PB59K)
Disassembly (Cont'd)
ST-31

4. Install worm gear assembly with rear housing into the gear
housing.
CAUTION:
lApply a thin coat of ATF inside gear housing and piston
before insertion.
lBe careful not to damage teflon ring at piston end when
inserting worm gear assembly into gear housing.
5. Gradually tighten rear housing bolts in a criss-cross fashion.
6. Install new O-ring into sector shaft cover.
lBefore installing, apply a thin coat of ATF to O-ring.
7. Install new U-packing into sector shaft cover.
lBefore installing, apply a thin coat of ATF to U-packing.
lDirect grooved side of U-packing to needle bearing.
8. Install sector shaft into sector shaft cover.
Set adjusting screw to its outermost position.
lBefore installing sector shaft, apply multi-purpose
grease to adjusting screw and adjusting screw shim.
9. Install new oil seal into gear housing with suitable tool.
lBefore installing oil seal, apply multi-purpose grease to
oil seal lips.
SST341C
SST326C
SST735C
SST321C
SST327C
POWER STEERING GEAR (Model: PB59K)
Assembly (Cont'd)
ST-32

10. Set piston rack at straight-ahead position.
Turn piston rack about 10É to 15É toward yourself with your
finger.
This enables smooth insertion of sector gear.
11. Gradually insert sector shaft into gear housing.
12. Tighten sector shaft cover bolts.
13. Set worm gear turning torque by turning sector shaft adjust-
ing screw and locking with lock nut.
Refer to ``TURNING TORQUE MEASUREMENT'', ``Pre-disas-
sembly and Adjustment'', ST-29.
lIf set and adjusting turning torque is considerably differ-
ent from the value before disassembly, replace the entire
assembly.
14. Check sector shaft end play in neutral position.
End play:
Less than 0.1 mm (0.004 in)
If not within specification, adjust it with adjusting screw.
15. Check worm gear preload. If not within specification, readjust
it.
ST696
SST328C
POWER STEERING GEAR (Model: PB59K)
Assembly (Cont'd)
ST-33

Disassembly and Assembly
Pre-disassembly Inspection
Disassemble the power steering oil pump only if the following
items are found.
lOil leak from any point shown in the figure.
lDeformed or damaged pulley.
lPoor performance.
AST167
SST984A
POWER STEERING OIL PUMP
ST-34