Lexus SC300 / Lexus SC400. Service manual - part 648

2.  REMOVE STARTER HOUSING, CLUTCH ASSEMBLY

AND GEARS
(a)  Remove the two mounting screws.

(b)  Remove the following parts from the magnetic switch:

(1) Starter 

housing

(2) Return 

spring

(3) Pinion 

gear

(4) Bearing
(5) Idler 

gear

(6) Clutch 

assembly

3. 

REMOVE STEEL BALL
Using a magnetic finger, remove the steel ball from the clutch
shaft hole.

4. 

REMOVE BRUSH HOLDER
Using a screwdriver, hold the spring back and disconnect the
brush from the brush holder. Disconnect the four brushes,
and remove the brush holder.

5. 

REMOVE ARMATURE FROM FIELD FRAME

ST–16

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STARTING SYSTEM

Starter

INSPECTION AND REPAIR OF STARTER
Armature Coil

1. 

INSPECT COMMUTATOR FOR OPEN CIRCUIT
Using an ohmmeter, check that there is continuity between
the segments of the commutator.
If there is no continuity, replace the armature.

2. 

INSPECT COMMUTATOR FOR GROUND
Using an ohmmeter, check that there is no continuity be-
tween the commutator and armature coil core.
If there is continuity, replace the armature.

Commutator

1. INSPECT 

COMMUTATOR 

FOR 

DIRTY 

AND 

BURNT

SURFACE
If the surface is dirty or burnt, correct with sandpaper
(No.400) or on a lathe.

2. 

INSPECT COMMUTATOR FOR RUNOUT
(a)  Place the commutator on V–blocks.
(b)  Using a dial indicator, measure the circle runout.

Maximum circle runout: 0.05 mm (0.0020 in.)

If the circle runout is greater than maximum, correct it on a
lathe.

3. INSPECT 

COMMUTATOR 

DIAMETER

Using a vernier caliper, measure the diameter.

Standard diameter: 35.0 mm (1.378 in.)

Minimum diameter: 34.0 mm (1.339 in.)

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

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STARTING SYSTEM

Starter

ST–17

4. 

INSPECT UNDERCUT DEPTH
Check that the undercut depth is clean and free of foreign
material. Smooth out the edge.

Standard undercut depth: 0.7–0.9 mm

(0.028–0.035 in.)

Minimum undercut depth: 0.2 mm (0.008 in.)

If the undercut depth is less than minimum, correct it with a
hacksaw blade.

Field Coil (Field Frame)

1. 

INSPECT FIELD COIL FOR OPEN CIRCUIT
Using an ohmmeter, check that there is continuity between
the lead wire and field coil brush lead.
If there is no continuity, replace the field frame.

2. 

INSPECT FIELD COIL FOR GROUND
Using an ohmmeter, check that there is no continuity be-
tween the field coil end and field frame.
If there is continuity, replace the field frame.

Brushes

INSPECT BRUSH LENGTH

Using a vernier caliper, measure the brush length.

Standard length:  15.0–15.5 mm

(0.591–0.610 in.)

Minimum length: 9.5 mm (0.374 in.)

If the length is less than minimum, replace the brush holder
and field frame.

ST–18

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STARTING SYSTEM

Starter

Brush Springs

INSPECT BRUSH SPRING LOAD

Take the pull scale reading the instant the brush spring sepa-
rates from the brush.

Standard installed load:

26–32 N (2.7–3.3 kgf, 6.0–7.3 lbf)

If the installed load is not as specified, replace the brush
springs.

Brush Holder

INSPECT BRUSH HOLDER INSULATION

Using an ohmmeter, check that there is no continuity be-
tween the positive (+) and negative (–) brush holders.
If there is continuity, repair or replace the brush holder.

Clutch and Gears

1. 

INSPECT GEAR TEETH
Check the gear teeth on the pinion gear, idler gear and the
clutch assembly for wear or damage.
If damaged, replace the gear or clutch assembly.
If damaged, also check the flywheel ring gear for wear or
damage.

2. 

INSPECT CLUTCH PINION GEAR
Rotate the pinion gear counterclockwise and check that it
turns freely. Try to rotate the pinion gear clockwise and check
that it locks.
If necessary, replace the clutch assembly.

Bearings

1. 

INSPECT FRONT BEARING
Turn each bearing by hand while applying inward force.
If resistance is felt or the bearing sticks, replace the bearing.

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STARTING SYSTEM

Starter

ST–19