LEXUS SC400 1991 Service Repair Manual

16. INSTALL RACK BOOTS, CLAMPS AND CLIPS
(a) Ensure that the tube hole is not clogged with grease.HINT: If the tube hole is clogged, the pressure inside the boot
will change after it is assembled and the steering wheel
turned.
(b) Install the boot.
NOTICE: Be careful not to damage or twist the boot.
(c) Install the clamp and clip to the boot.
17. INSTALL TIE ROD ENDS
(a) Screw the lock nut and tie rod end onto the rack end until the matchmarks are aligned.
(b) After adjusting toe±in, torque the lock nut.
Torque: 56 N Vm (570 kgf Vcm, 41 ft Vlbf)
18. INSTALL RIGHT AND LEFT TURN PRESSURE TUBES
(a) Install a new union seat.
(b) Using SST, tighten nut.
SST 09633±00020
Torque: 24 N Vm (240 kgf Vcm, 17 ft Vlbf)
HINT: Use a torque wrench with a fulcrum length of 300 mm
(11.81 in.).
(c) Install the union bolt over the new gaskets and torque it.
Torque: 34 N Vm (350 kgf Vcm, 25 ft Vlbf)
SR±162±
STEERING POWER STEERING
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ELECTRONIC CONTROL SYSTEM
PRECAUTION
SR0GR±01
Do not open the cover or the case of the ECU and various computers unless \
absolutely necessary.
(If the IC terminals are touched, the IC may be destroyed by static ele\
ctricity.)
ELECTRONIC CIRCUIT
SR0GS±04
±
STEERING POWER STEERINGSR±163
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TROUBLESHOOTING FLOW±CHART
SR0GT±04
Trouble

Hard steering at idle or low±speed driving.

Steering too sensitive during high±speed driving.
Preliminary Check

Check tire pressure.

Check lubrication of suspension and steering linkage.

Check front wheel alignment.

Check steering system joint and suspension arm ball joint.

Check for bent steering column.

Check that all connectors are secure.

Check PS pump fluid pressure. (See page SR±115)
SR±164±
STEERING POWER STEERING
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BE±136).
±
STEERING POWER STEERINGSR±165
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SR±166±
STEERING POWER STEERING
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ELECTRONIC CONTROL COMPONENTS
INSPECTION
SOLENOID VALVE
SR0GU±01
1. DISCONNECT WIRING CONNECTOR
2. MEASURE RESISTANCEMeasure the resistance between SOL
and SOL .
Resistance:
6.0±11.0

3. CHECK SOLENOID OPERATION
(a) Connect the battery positive terminal to the solenoid terminal
SOL
.
(b) C onnect the battery negative terminal to the solenoid
terminal SOL .
(c) Check that the solenoid is clicked. If faulty, replace the pressure control valve with the solenoid
valve.
NOTICE:
w Do not apply voltage for more than 30 seconds to avoid
burning out the solenoid.
w If repeating this step, wait until the solenoid cools down
enough that it can be touched by hand.
4. CONNECT WIRING CONNECTOR
±
STEERING POWER STEERINGSR±167
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POWER STEERING ECU
1. JACK UP VEHICLE AND SUPPORT IT ON STANDS
2. START ENGINE
3. MEASURE VOLTAGE OF ECU
(a) Using a voltmeter, measure the voltage between ECUterminals SOL  and GND while the engine is idling.
Standard voltage:
0.3±0.5 V
(b) Place the transmission in gear and while running at about 37
mph (60 km/h), measure the voltage between ECU terminals
SOL  and GND.
Standard voltage:
Voltage measured in (a) above, minus
(IUZ±FE Engine)
0.07±0.02 V
(2JZ±FE Engine)
0.05±0.18 V
If no voltage, try another ECU.
4. LOWER VEHICLE
SR±168
±
STEERING POWER STEERING
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SERVICE SPECIFICATIONS
SERVICE DATA
SR0GP±01\
 \
Steering wheel freeplay Maximum\
\
30 mm (1.18 in.)
\
 \
STEERING COLUMN\
\
\
 \
Pawl stopper Mark\
\
\
 \
1 or A\
\
12.68±12.74 mm (0.4992±0.5016 in.)
\
 \
2 or B\
\
12.61±12.67 mm (0.4965±0.4988 in.)
\
 \
3 or C\
\
12.54±12.60 mm (0.4937±0.4961 in.)
\
 \
4 or D\
\
12.47±12.53 mm (0.4909±0.4933 in.)
\
 \
5 or E\
\
12.40±12.46 mm (0.4882±0.4906 in.)
\
 \
6 or F\
\
12.33±12.39 mm (0.4854±0.4878 in.)
\
 \
7 or G\
\
12.26±12.32 mm (0.4827±0.4850 in.)
\
 \
PS ON±VEHICLE INSPECTION\
\
\
 \
Maximum rise of oil level\
\
Below 5 mm (0.20 in.)
\
 \
Oil pressure at idle speed with valve closed Minimum\
\
7,355±7,845 kPa (75±80 kgf/cm2, 1,067±1,137 psi)
\
 \
Steering effort at idle speed Maximum\
\
40 N (4.1 kgf, 9.0 lbf)
\
 \
PS PUMP\
\
\
 \
Rotor shaft bushing oil clearance (SC 400) STD\
\
0.01±0.03 mm (0.0004±0.0012 in.)
\
 \
Rotor shaft bushing oil clearance (SC 400) Maximum\
\
0.07 mm (0.0028 in.)
\
 \
Rotor shaft bushing oil clearance (SC 300) STD\
\
0.03±0.05 mm (0.0012±0.0020 in.)
\
 \
Rotor shaft bushing oil clearance (SC 300) Maximum\
\
0.07 mm (0.0028 in.)
\
 \
Vane plate to rotor groove clearance (SC 400)\
\
0.03 mm (0.0012 in.) or less
\
 \
Vane plate to rotor groove clearance (SC 300)\
\
0.04 mm (0.0016 in.) or less
\
 \
Vane plate length (SC 400) Minimum\
\
14.97 mm (0.5894 in.)
\
 \
Vane plate height (SC 400) Minimum\
\
8.0 mm (0.315 in.)
\
 \
Vane plate thickness (SC 400) Minimum\
\
1.77 mm (0.0697 in.)
\
 \
Vane plate length (SC 300) Minimum\
\
14.97 mm (0.5894 in.)
\
 \
Vane plate height (SC 300) Minimum\
\
8.5 mm (0.335 in.)
\
 \
Vane plate thickness (SC 300) Minimum\
\
1.37 mm (0.0539 in.)
\
 \
Vane plate length (SC 400) Rotor and cam ring mark\
\
\
 \
NONE\
\
14.996±14.998 mm (0.59039±0.59047 in.)
\
 \
1\
\
14.994±14.996 mm (0.59031±0.59039 in.)
\
 \
2\
\
14.992±14.994 mm (0.59023±0.59031 in.)
\
 \
3\
\
14.990±14.992 mm (0.59016±0.59024 in.)
\
 \
4\
\
14.988±14.990 mm (0.59007±0.59016 in.)
\
 \
Vane plate length (SC 300) Rotor and cam ring mark\
\
\
 \
NONE\
\
14.999±15.001 mm (0.59051±0.59059 in.)
\
 \
1\
\
14.997±14.999 mm (0.59043±0.59051 in.)
\
 \
2\
\
14.995±14.997 mm (0.59035±0.59043 in.)
\
 \
3\
\
14.993±14.995 mm (0.59027±0.59035 in.)
\
 \
4\
\
14.991±14.993 mm (0.59020±0.59027 in.)
±
STEERING SERVICE SPECIFICATIONSSR±169
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\
 \

Flow control valve spring length (SC 400) STD\
\
37 mm (1.46 in.)
\
 \
Flow control valve spring length (SC 400) Minimum\
\
36 mm (1.42 in.)
\
 \
Flow control valve spring length (SC 300) STD\
\
35 mm (1.38 in.)
\
 \
Flow control valve spring length (SC 300) Minimum\
\
33 mm (1.30 in.)
\
 \
Pump rotating torque (SC 400)\
\
0.1 NVm (1.0 kgf Vcm, 0.9 in. Vlbf) or less
\
 \
Pump rotating torque (SC 300)\
\
0.2 N Vm (2.5 kgf Vcm, 2.2 in. Vlbf) or less
\
 \
PS GEAR HOUSING\
\
\
 \
Steering rack runout Maximum\
\
0.3 mm (0.012 in.)
\
 \
Total preload\
\
0.9±1.9 N Vm (9±20 kgf Vcm, 7.9±17.3 in. Vlbf)
\
 \
Solenoid valve resistance\
\
6±11

SR±170±
STEERING SERVICE SPECIFICATIONS
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TORQUE SPECIFICATIONS
SR0GQ±01\
 \
Part tightened NVm kgf Vcm ft Vlbf\
 \
STEERING COLUMN   
\
 \
Steering wheel 35 360 26\
 \
Steering wheel pad 7.4 75 65 in. Vlbf\
 \
Column bracket X Body 25 260 19\
 \
Sliding yoke 35 360 26\
 \
(Power tilt and power telescopic steering column)   
\
 \
Tilt steering housing support X Lower tube 13 130 9\
 \
Support stopper bolt lock nut 2.9 30 26 in. Vlbf\
 \
Connector bracket 4.9 50 43 in. Vlbf\
 \
Telescopic sensor plate 4.9 50 43 in. Vlbf\
 \
Telescopic adjusting screw 6.9 70 61 in. Vlbf\
 \
Telescopic adjusting screw lock nut 31 320 23\
 \
(Manual tilt and Manual telescopic steering column)   
\
 \
Tilt memory bolt 6.4 65 56 in. Vlbf\
 \
Tilt memory bolt set nut 5.9 60 52 in. Vlbf\
 \
Tilt lever assembly installation bolt 2.9 30 26 in. Vlbf\
 \
Tilt pawl set nut 5.9 60 52 in. Vlbf\
 \
Tilt lever retainer set nut 15 150 11\
 \
Compression spring bushing bolt 7.8 80 69 in. Vlbf\
 \
Steering column tube stopper bolt 19 195 14\
 \
Serration attachment set nut 13 130 9\
 \
Telescopic lever set bolt 25 260 19\
 \
Connector bracket set bolt 4.9 50 43 in. Vlbf\
 \
POWER STEERING PUMP   
\
 \
(SC 400)   
\
 \
PS pump installation bolt 39 400 29\
 \
PS pump installation nut 43 440 32\
 \
Pressure tube X Pressure port union 49 500 36\
 \
Drive pulley X Rotor shaft 43 440 32\
 \
Front housing X Rear bracket 39 400 29\
 \
Pressure port union X Pump housing 69 700 51\
 \
Suction port union X Pump housing 13 130 9\
 \
(SC 300)   
\
 \
PS pump installation bolt 58 590 43\
 \
Pressure tube X Pressure port union 49 500 36\
 \
Drive pulley X Rotor shaft 43 440 32\
 \
Front housing X Rear housing 17 170 12\
 \
Pressure port union X Pump housing 83 850 61\
 \
Reservoir tank X Pump housing Front side bolt 13 130 9\
 \
Rear side bolts 17 170 12
±
STEERING SERVICE SPECIFICATIONSSR±171
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