Lexus SC300 / Lexus SC400. Manual — part 325

4.

INSPECT DRIVE AND DRIVEN ROTORS

A.

Install casing and rotors to rear housing
Face 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

–

COOLIING SYSTEM

Electronically Controlled Hydraulic
Cooling Fan (Hydraulic Pump)

CO–35

5.

INSPECT OIL CLEARANCE OF DRIVE SHAFT
(a) Using a caliper gauge, measure the bushing inside

diameter 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

CO–36

–

COOLIING SYSTEM

Electronically Controlled Hydraulic
Cooling Fan (Hydraulic Pump)

REPLACEMENT OF OIL SEAL

1.

REMOVE OIL SEAL
Using SST and a hammer, tap out the oil seal.
SST 09631–10030

2.

INSTALL OIL SEAL
(a) Using a 22 mm socket wrench and hammer, tap in a new

oil seal until its surface is flush with the housing edge.

(b) Apply fluid to the oil seal lip.

ASSEMBLY OF HYDRAULIC PUMP

(See Components on page

CO–31

)

HINT:

•

Thoroughly clean all parts to be assembled.

•

Before installing the parts, apply new fluid to all sliding
and rotating surfaces.

1.

MOUNT REAR HOUSING
HINT: Mount the parts in a vise as shown in the illustration.

2.

INSTALL SPOOL VALVE
(a) Align the small hole of the spool sleeve with the hole of

the rear housing, and insert the spool body into the rear
housing.

–

COOLIING SYSTEM

Electronically Controlled Hydraulic
Cooling Fan (Hydraulic Pump)

CO–37

(b) Insert the compression spring and spool valve into the

rear housing.

(c) Install a new O–ring to the end plug.
(d) Apply fluid to the O–ring.
(e) Temporarily install the end plug.

(f)

Insert a 5 mm (0.19 in.) straight pin through the holes of
the rear housing and spool sleeve.

(g) Using a 10 mm hexagon wrench, install the end plug.

Torque: 19 N

⋅

m (200 kgf

⋅

cm, 14 ft

⋅

lbf)

(h) Pull out the straight pin.

CO–38

–

COOLIING SYSTEM

Electronically Controlled Hydraulic
Cooling Fan (Hydraulic Pump)