LEXUS SC400 1991 Service Repair Manual

ASSEMBLY OF ALTERNATOR
(See Components on page CH±10)
1. PLACE RECTIFIER END FRAME ON PULLEY
2. INSTALL ROTOR TO RECTIFIER END FRAME
3. INSTALL RECTIFIER END FRAME (a) Place the alternator washer on the rotor.
(b) Using a 29 mm socket wrench and press, slowly pressin the rectifier end frame.
(c) Install the four mounting nuts.
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CHARGING SYSTEM AlternatorCH±17
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4. INSTALL PULLEY(a) Install the pulley to the rotor shaft by tightening thepulley nut by hand.
(b) Hold SST (A) with a torque wrench, and tighten SST (B)
clockwise to the specified torque.
SST 09820±63010
Torque: 39 N Vm (400 kgf Vcm, 29 ft Vlbf)
(c) Check that SST (A) is secured to the pulley shaft.
(d) As shown in the illustration, mount SST (C) in a vise, and
install the alternator to SST (C).
(e) To torque the pulley nut, turn SST (A) in the direction shown in the illustration.
Torque: 110 N Vm (1,125 kgf Vcm, 81 ft Vlbf)
(f) Remove the alternator from SST (C).
(g) Turn SST (B) and remove SST (A and B).
5. INSTALL RECTIFIER HOLDER (a) Place the seal plate on the rectifier end frame.
(b) Install the four rubber insulators on the lead wires.
(c) Install the rectifier holder with the four screws.
CH±18
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CHARGING SYSTEM Alternator
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6. INSTALL IC REGULATOR AND BRUSH HOLDER(a) Place the IC regulator together and brush holder on therectifier end frame.
NOTICE: Be careful of the holder installation direction.
(b) Install the five mounting screws until there is a clearance
of approx. 1 mm (0.04 in.) between the brush holder and
connector.
(c) Place the brush holder cover on the brush holder.
7. INSTALL REAR END COVER (a) Install the end cover with the three nuts.
(b) Install the terminal insulator with the nut.
8. CHECK THAT ROTOR ROTATES SMOOTHLY
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CHARGING SYSTEM AlternatorCH±19
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INSTALLATION OF ALTERNATOR
(See Components on page CH±9)
1. INSTALL ALTERNATOR (a) Install the alternator and A/T oil cooler bracket with the
bolt and nut.
Torque: 37 N Vm (380 kgf Vcm, 27 ft Vlbf)
(b) Connect the alternator connector.
(c) Connect the alternator wire with the nut and cap.
2. INSTALL DRIVE BELT Install the drive belt by turning the drive belt tensioner coun-
terclockwise.
HINT: The pulley bolt for the belt tensioner has a left±hand
thread.
3. CONNECT CABLE TO NEGATIVE TERMINAL OF BATTERY
4. PERFORM ON±VEHICLE INSPECTION (See steps 6 to 8 on pages CH±6 to 8)
5. INSTALL ENGINE UNDER COVER
CH±20
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CHARGING SYSTEM Alternator
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SERVICE SPECIFICATIONS
SERVICE DATA
BatterySpecific gravity1.27±1.29
(when fully charged at 205C (68 5F))
AlternatorRated output12 V±100 A
Rotor coil resistance2.8±3.0

Slip ring diameterSTD 14.2±14.4 mm0.559±0567 in.
Limit 12.8 mm0.504 in.
Brush exposed lengthSTD 10.5 mm0.413 in.
Limit 1.5 mm0.059 in.
AlternatorRegulating voltageat 255C (77 5F)13.9±15.1 V
regulatorat 115 5C (239 5F)13.5±14.3 V
TORQUE SPECIFICATIONS
Part tightenedN Vmkgf Vcmft Vlbf
Alternator pulley X Rotor11 01,12581
Alternator X Alternator bracket37380 27
Alternator X Cylinder block3738027
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CHARGING SYSTEM Service SpecificationsCH±21
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COOLING SYSTEM
CO±1±
COOLIING SYSTEM Description
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DESCRIPTION
This engine utilizes a pressurized forced circulation cooling system which i\
ncludes a hermostat equipped
with a by±pass valve mounted on the inlet side. The cooling system is composed of the water jacket (inside the cylinder bl\
ock and cylinderhead), radiator,
water pump, thermostat, cooling fan, hoses and other components.
OPERATION
CO±2±
COOLIING SYSTEM Description
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DESCRIPTION
This engine utilizes a pressurized forced circulation cooling system whi\
ch includes a hermostat equipped
with a by±pass valve mounted on the inlet side. The cooling system is composed of the water jacket (inside the cylinder bl\
ock and cylinderhead), radiator,
water pump, thermostat, cooling fan, hoses and other components.
OPERATION
CO±2±
COOLIING SYSTEM Description
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Coolant which is heated in the water jacket is pumped to the radiator, through which a cooling fan blows
air to cool the coolant as it passes through. Coolant which has been coo\
led is then sent back to the engine by
the water pump, where it cools the engine. The water jacket is a network of channels in the shell of the cylinder bloc\
k and cylinderhead through which
coolant passes. It is designed to provide adequate cooling through the cylinders and combus\
tion chambers
which become heated during engine operation.
RADIATOR The radiator performs the function of cooling the coolant which has pass\
ed through the waterjacket and
become hot, and it is mounted in the front of the vehicle. The radiator consis\
ts of an upper tank and lower tank,
and a core which connects the two tanks. The upper tank contains the inlet \
for coolant from the water jacket
and the filler inlet. It also has a hose attached through which excess cool\
ant or steam can flow. The lower tank
contains the outlet for coolant and drain plug. The core contains many t\
ubes through which coolant flows from
the upper tank to the lower tank as well as cooling fins which radiate heat\
away from the coolant in the tubes.
The air sucked through the radiator by the cooling fan, as well as the wind generated by the ve\
hicle's travel,
passes through the radiator, cooling the coolant. Models with automatic transmission include an aut\
omatic
transmission fluid cooler built into the lower tank of the radiator. A cooling fan is mounted behind radiator to assist
the flow of air through the radiator. When the coolant temperature is low, the fan operates slowly to help the warm
up, and when the coolant temperature becomes high, the fan speed is increas\
ed to provide the air flow required
for cooling.
RADIATOR CAP (on Reservoir Tank)
The radiator cap is a pressure type cap which seals the radiator, resulting in pressurization of the radiator
as the coolant expands. The pressurization prevents the coolant from boi\
ling even when the coolant tempera-
ture exceeds 100 5C (212 5F). A relief valve (pressurization valve) and a vacuum valve (negati\
ve pressure valve)
are built into the radiator cap. The relief valve opens and lets steam esca\
pe through the overflow pipe when
the pressure generated inside the cooling system exceeds the limit (coolant temperature: 110±120 5C
(230±248 5F) pressure; 29.4±98.1 kPa (0.3±1.0 kgf/cm2, 4.3±14.2 psi)). The vacuum v\
alve opens to alleviate
the vacuum which develops in the coolant system after the engine is stopped\
and the coolant temperature
drops.
RESERVOIR TANK The purpose of the reservoir tank is to catch coolant overflows created by \
volumetrix expansion when the
coolant temperature increases. The cap of the reservoir tank is a pressure type\
which prevents deterioration
of the LLC (Long Life Coolant) caused by contact with atmospheric air, increases vaporization performance and
reduces loss of the coolant volume.
WATER PUMP The water pump is mounted on the front of the cylinder block and driven by t\
he reverse side of the timing
belt.
THERMOSTAT The thermostat has a wax type by±pass valve and is mounted in the wat\
er inlet housing. The thermostat
begins to open at the temperature of 80 5C (180 5F). When the coolant temperature is low, the valve closes to
prevent coolant flow to the radiator, thus permitting the engine to warm up rapidly. When the by±pass valve
opens the by±pass circuit, the engine coolant continues to circulate \
inside the engine, quickly and uniformly
warming up to the appropriate temperature. When the coolant temperature is high\
, the valve opens and coolant
flows to the radiator where it is cooled. When the wax inside the thermostat \
is heated, it expands and thus
creates pressure which overpowers the force of the spring which keeps the valve\
closed. When the wax cools,
its contraction causes the force of the spring to take effect once more, closing the valve.
ELECTRONICALLY CONTROLLED HYDRAULIC COOLING FAN (See page CO±22)
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COOLIING SYSTEM DescriptionCO±3
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PREPARATION
SST (SPECIAL SERVICE TOOLS)
 Illustration Part No. Part Name Note
 


 

09278±54012
 

Drive Shaft Holding Tool
 


Hydraulic pump pulley
 




 



09286±46011
 




Injection Pump
Spline Shaft Puller
 




Hydraulic pump pulley
 




 



09620±30010
 




Steering Gear Box
Replacer Set
 




 




 



(09627±30010)
 




Steering Sector Shaft
Bushing Replacer
 




Oil seal for hydraulic motor
 




 




(09631±00020)
 




(Handle)
 




Oil seal for hydraulic motor
 




 




09631±10030
 




Oil Seal Remover
 




Oil seal for hydraulic pump
 




 




09843±18020
 




Diagnosis Check
Wire 




RECOMMENDED TOOLS 

Illustration
 

Part No.
 

Part Name
 

Note
 




 




09025±00010
 




Small Torque
Wrench 




For measuring preload
 


 

09082±00015 


TOYOTA
Electrical tester 


 




 



09200±00010
 




Engine Adjust
Kit
 




 




 



09258±00030
 



Hose Plug Set
 




Plug for the vacuum hose, oil hose ect.
 




 




09904±00010
 




Expander
Set
 




Oil seal for hydraulic pump
 




 




09905±00013
 




Snap Ring
Pliers
 




Oil seal for hydraulic pump
CO±4±
COOLIING SYSTEM Preparation
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