Isuzu engine 4j series. Manual - part 88

6D3 – 10  CHARGING SYSTEM

6. Rotor

•

With the rotor gripped with a vise, remove the pulley
nut 

!

, and then take off the pulley 

"

, fan 

#

, front

cover 

$

 and the rotor 

%

.

7. Rear Bearing

8.  Terminal Bolt and Nut

9. Rear 

Cover

•

Remove the nuts fixing the B terminal and diode
holder.
Separate the stator and rear cover.
Note the position of insulation washers to ensure
reassembly into original position.

10. Stator

11. Diode

•

Separate the diodes from the stator by melting away
solder on stator coil and diode.
When melting solder, hold the lead wire with long nose
pliers to prevent heat from being transferred to the
diodes.

12. IC Regulator Assembly

•

Separate the IC regulator from the diode by melting
away solder on IC regulator holder plate and removing
the nut.

13. Brush Holder

•

Remove the serrated bolts and melt away solder on IC
regulator.

•

Do not remove the serrated bolts unless the
replacement of brush or condenser.
To install, follow the removal steps in the reverse
order.

INSPECTION AND REPAIR

Repair or replace necessary parts if extreme wear or
damage is found during inspection.

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CHARGING SYSTEM  6D3 – 11

ROTOR

1. Check the rotor slip ring surfaces for contamination and

roughness.  If rough, polish with #500-600 sandpaper.

2. Measure the slip ring diameter, and replace if it

exceeds the limit.

mm (in)

Standard

Limit

34.6 (1.36)

33.6 (1.32)

3. Check for continuity between slip rings, and replace if

there is no continuity.

4. Check for continuity between slip ring and rotor core or

slip ring and rotor shaft.
In case of continuity, replace the rotor assembly.

Rear Ball Bearing
Check to see if the ball bearing rotates smoothly with no
noises.
When it does not rotate smoothly or any noises are heard,
replace it with a new one.
When installing the bearing, press it in with the stopper ring
turned to the spline side, while pushing the bearing inner ring.
Bearing press-in measurement: L

mm (in)

Standard

41.8 - 42.0 (1.64 - 1.65)

STATOR COIL

1. Check for continuity between respective phases.

In case of no continuity, replace the stator.

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6D3 – 12  CHARGING SYSTEM

2. Check for continuity across one of the stator coils and

stator core.  If a continuity exists, replace the coil.

DIODE

1. Check for continuity across the terminal (example:

across BAT and U).  If a continuity exists, the diode is
in satisfactory condition.  If no continuity exists the
diode is defective.

2. Make a test with the polarities reversed.  If no

continuity exists, the diode is in satisfactory condition.
If a continuity exists at any point, the diode is defective
and should be replaced.
Auxiliary diodes are not provided with the terminal and
continuity test should be made across the terminals of
the conventional diodes.

-  side diode check

Across terminals

BAT (Positive side (+) diodes)

Tester pin

Positive side

Negative side

Positive side

No continuity

U.V.W

Negative side

Continuity

+  side diode check

Across terminals

E (Negative side (+) diodes)

Tester pin

Positive side

Negative side

Positive side

Continuity

U.V.W

Negative side

No continuity

BRUSH

Measure length of brushes.
Brush length (L)

mm (in)

Standard

Limit

20 (0.79)

6 (0.24)

Brushes are provided with a line which indicates the limit
of usage.

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CHARGING SYSTEM  6D3 – 13

IC REGULATOR

Measuring instruments is necessary.
Take the following measurements with the instruments
connected as shown in the illustration.

V1  Voltage at BAT1

V

Standard

10 - 13

V2 Voltage across F-E

V

Standard

Limit

2 or less

2 or more

Take measurement with `S' terminal disconnected.
V3 Measure the voltage at BAT1 - BAT2.

V

Standard

20 - 26

•

Measurement the voltage across the E-F while varying
resistance gradually from zero using variable resistor.
Then check that voltage increases from 2V to 10 - 13.
If increase in voltage is interrupted at any point,
replace the regulator.

•

V4 Measure the voltage across the intermediate tap on
variable resistor and `E' terminal without actuating the
variable resistor.

V

Standard voltage at 20°C (68°F)

14.0 - 14.9

If measured value deviates from the standard, replace
the regulator.

Check the following with the instrument connected as
illustrated.
Measure the voltage across the terminals B and E by
gradually increasing voltage with variable resistor RV.
Check to see if voltage increases from lower than 2V to
range from 10 to 13 volts.
If the voltage does not vary, the regulator is defective and
should be replaced.
Check the voltage across the intermediate tap of the
variable resistor and terminal E without actuating the
variable resistor.

V

Standard voltage at 20°C (68°F)

14.5 - 16.9

If measured voltage deviates from the standard value,
replace the regulator.

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