1991 LEXUS SC400 cooling

10. REMOVE LH ENGINE WIRE COVERRemove the two bolts and engine wire cover.
11. REMOVE VSV FOR EVAP SYSTEM Remove the two bolts, and disconnect the VSV from cylinder
head and timing belt cover.
12. REMOVE RH NO.3 TIMING BELT COVER Remove the three bolts and timing belt cover.
13. REMOVE LH NO.3 TIMING BELT COVER (a) Remove the four mounting bolts.
(b) Disconnect the cord grommet from the timing belt cover,
and remove the timing belt cover.
(c) Remove the cord grommet from the high±tension cord.
14. DISCONNECT RADIATOR HOSE FROM WATER INLET
15. REMOVE DRIVE BELT IDLER PULLEY Remove the pulley bolt, cover plate and idler pulley.
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15. REMOVE RH NO.2 TIMING BELT COVER(a) Disconnect the cam position sensor connector from theignition coil bracket.
(b) Disconnect the cam position sensor wire from the clamp
on the timing belt cover.
(c) Remove the five mounting bolts.
(d) Disconnect the wire clamp from the timing belt cover,
and remove the timing belt cover and four gasket.
16. REMOVE LH NO.2 TIMING BELT COVER (a) Disconnect the cam position sensor wire from the clamp
on the timing belt cover.
(b) Disconnect the cam position sensor connector.
(c) Remove the three mounting bolts.
(d) Disconnect the connector grommet from the timing belt cover, and remove the timing belt cover and two
gaskets.
17. DISCONNECT PRESSURE AND SUCTION HOSES FROM HYDRAULIC PUMP
18. REMOVE HYDRAULIC PUMP (a) Disconnect the solenoid valve connector.
(b) Remove the two mounting bolts and two nuts.
(c) Disconnect the engine speed sensor wire clamp.
(d) Remove the hydraulic pump.
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COMPONENTS FOR DISASSEMBLY AND
ASSEMBLY
DISASSEMBLY OF HYDRAULIC PUMP
1. REMOVE SUCTION PORT UNION(a) Remove the mounting bolt.
(b) Pull out the port union.
(c) Remove the O±ring from the port union.
2. REMOVE WIRE CLAMP (a) Disconnect the wire clamp from the rear housing.
(b) Remove the wire clamp from the read wire.
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3. MOUNT REAR HOUSINGHINT: Mount the parts in a vise as shown in the illustration.
4. REMOVE SOLENOID VALVE (a) Remove the solenoid valve.
(b) Remove the O±ring from the solenoid valve.
(c) Remove the O±ring from the rear housing.
5. REMOVE PUMP PULLEY (a) Using SST, remove the pulley nut by turning it clockwise.
SST 09278±54012
(b) Using SST, remove the pulley.
SST 09286±46011
6. REMOVE FRONT HOUSING (a) Remove the five mounting bolts.
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COOLIING SYSTEM Electronically Controlled Hydraulic
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(b) Using a plastic±faced hammer, carefully tap out the front
housing.
(c) Remove the O±ring from the casing.
7. REMOVE FRONT THRUST WASHER AND DRIVE SHAFT
8. REMOVE DRIVE AND DRIVEN ROTORS
9. REMOVE REAR THRUST WASHER
10. REMOVE CASING (a) Remove the casing.
(b) Remove the O±ring from the rear housing.
11. REMOUNT REAR HOUSING HINT: Mount the parts in a vise as shown in the illustration.
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12. REMOVE SPOOL VALVE(a) Using a 10 mm hexagon wrench, remove the end plugand following parts:
(1) Spool valve
(2) Compression spring
(3) Spool sleeve
(b) Remove the O±ring from the end plug.
INSPECTION OF HYDRAULIC PUMP
1. CLEAN DISASSEMBLED PARTS Using a cleaner and compressed air, clean the disassembled
parts.
CAUTION: Thoroughly clean the oil passages of the rear
housing. Oil passage A includes a filter which should be
cleaned carefully.
2. INSPECT SPOOL VALVE (a) Coat the spool valve with PS fluid, and check that it falls
smoothly into the spool sleeve by its own weight.
(b) Check the spool valve for leakage. Close one of the holes and apply compressed air
392±490 kPa (4±5 kgf/cm2, 57±71 psi) into the opposite
side, check that air does not come out of the end hole.
If it doesn't, replace the spool valve and sleeve as a set.
3. INSPECT SPOOL COMPRESSION SPRING Using a vernier calipers, measure the free length of the com-
pression spring.
Free length: 45.8 mm (1.803 in.)
If the free length is not as specified, replace the compression
spring.
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4. INSPECT DRIVE AND DRIVEN ROTORS
A. Install casing and rotors to rear housingFace the dot mark of the rotors upward.
B. Inspect rotor side clearance HINT: Before measuring the clearance, remove one side of
the rotor.
Using a feeler gauge and precision straight edge, measure
the clearance between the rotor and precision straight edge.
Standard side clearance:
Drive rotor 0.02 mm (0.0008 in.)
Driven rotor 0.03 mm (0.0012 in.)
Maximum side clearance: Drive rotor 0.03 mm (0.0012 in.)
Driven rotor 0.04 mm (0.0016 in.)
If the clearance is greater than maximum, replace the rotors
as a set. If necessary, replace the housings.
C. Inspect rotor body clearance Using a feeler gauge, measure the clearance between the
driven rotor and casing.
Standard body clearance: 0.05±0.09 mm
(0.0020±0.0035 in.)
Maximum body clearance: 0.10 mm (0.0039 in.)
If the clearance is greater than maximum, replace the rotors
as a set. If necessary, replace the casing.
D. Inspect rotor tip clearance Using a feeler gauge, measure the clearance of all the six
drive rotor tips between the drive and driven rotors.
Standard tip clearance: 0.02 mm (0.0008 in.)
Maximum tip clearance: 0.03 mm (0.0012 in.)
If the clearance is greater than maximum, replace the rotors
as a set.
E. Remove rotors and causing from rear housing
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5. INSPECT OIL CLEARANCE OF DRIVE SHAFT(a) Using a caliper gauge, measure the bushing insidediameter on the housing.
Bushing inside diameter: 17.00±17.05 mm
(0.6693±0.6713 in.)
(b) Using a micrometer, measure the drive shaft diameter.
Shaft diameter: 16.97±16.98 mm(0.6681±0.6685 in.)
(c) Subtract the drive shaft diameter measurement from the
bushing inside diameter measurement.
Standard clearance: 0.02±0.08 mm
(0.0008±0.0031 in.)
Maximum clearance: 0.08 mm (0.0031 in.)
If the clearance is greater than maximum, replace the shaft.
If necessary, replace the housings.
6. INSPECT SOLENOID VALVE RESISTANCE Using an ohmmeter, measure the resistance between the ter-
minals.
Resistance (Cold): 7.5±8.5

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