Lexus SC300 / Lexus SC400. Manual — part 287

(c) Remove the alternator washer.

6.

REMOVE ROTOR FROM DRIVE END FRAME

INSPECTION AND REPAIR OF
ALTERNATOR
Rotor

1.

INSPECT ROTOR FOR OPEN CIRCUIT
Using an ohmmeter, check that there is continuity between
the slip rings.

Standard resistance (Cold): 2.8–3.0

If there is no continuity, replace the rotor.

2.

INSPECT ROTOR FOR GROUND
Using an ohmmeter, check that there is no continuity be-
tween the slip ring and rotor.
If there is continuity, replace the rotor.

3.

INSPECT SLIP RINGS
(a) Check that the slip rings are not rough or scored.
If rough or scored, replace the rotor.
(b) Using a vernier caliper, measure the slip ring diameter.

Standard diameter: 14.2–14.4 mm

(0.559–0.567 in.)

Minimum diameter: 12.8 mm (0.504 in.)

If the diameter is less than minimum, replace the rotor.

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CHARGING SYSTEM

Alternator

CH–13

Stator (Drive End Frame)

1.

INSPECT STATOR FOR OPEN CIRCUIT
Using an ohmmeter, check that there is continuity between
the coil leads.
If there is no continuity, replace the drive end frame assem-
bly.

2.

INSPECT STATOR FOR GROUND
Using an ohmmeter, check that there is no continuity be-
tween the coil lead and drive end frame.
If there is continuity, replace the drive end frame assembly.

Brushes

INSPECT EXPOSED BRUSH LENGTH

Using a vernier caliper, measure the exposed brush length.

Standard exposed length: 10.5 mm (0.413 in.)

Minimum exposed length: 1.5 mm (0.059 in.)

If the exposed length is less than minimum, replace the brush
holder.

Rectifiers (Rectifier Holder)

1.

INSPECT POSITIVE RECTIFIER
(a) Using an ohmmeter, connect one tester probe to the

positive (+) terminal and the other to each rectifier
terminal.

(b) Reverse the polarity of the tester and repeat (a).
(c) Check

that one shows continuity and the other shows no

continuity.

If continuity is not as specified, replace the rectifier holder.

2. INSPECT

NEGATIVE

RECTIFIER

(a) Using an ohmmeter, connect one tester probe to each

negative (–) terminal and the other to each rectifier
terminal.

(b) Reverse the polarity of the tester probes and repeat (a).
(c) Check

that one shows continuity and the other shows no

continuity.

If continuity is not as specified, replace the rectifier holder.

CH–14

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CHARGING SYSTEM

Alternator

Bearings

1.

INSPECT FRONT BEARING
Check that the bearing is not rough or worn.

2.

IF NECESSARY, REPLACE FRONT BEARING
(a) Remove the four screws, bearing retainer and bearing.

(b) Using

a

socket wrench and press, press out the bearing.

(c) Using SST and a press, press in a new bearing.
SST 09608–20012 (09608–00030)

(d) Install the bearing retainer with the four screws.

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CHARGING SYSTEM

Alternator

CH–15

3.

INSPECT REAR BEARING
Check that the bearing is not rough or worn.

4.

IF NECESSARY, REPLACE REAR BEARING
(a) Using SST, remove the bearing cover and bearing.
SST 09820–00021
NOTICE: Be careful not to damage the fan.

(b) Using SST and a press, press in a new bearing.
SST 09820–00030

(c) Using SST, push in the bearing cover.
SST 09285–76010

CH–16

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CHARGING SYSTEM

Alternator