4M40 DIESEL ENGINE SHOP MANUAL Electrical Caterpillar

Specifications

Alternator

Starter, Preheat

Structure And Operation

Starter

* This starter uses planetary gears as its reduction gearing mechanism.

Alternator

<24V-35A>

Circuit Diagram

Troubleshooting

Power And Charging

Engine Starting, Preheating and Stopping

#180 to #249 Relay, #250 to #349 Sensor, #750 to #859 Other

#187 Inspection of starter relay

* Perform continuity check and operation check, and if any fault is found, replace the relay.

#231 Inspection of safety relay

* Measure the resistance values between terminals 2 and 3.

* If the measured value deviates from the standard value, replace the relay.

#262 Inspection of water temperature sensor

* Dip the sensor in a container filled with engine oil.

* Raise the oil temperature to the specified one while stirring oil.

* Measure the resistance between terminals 1 and 2.

* If the measured value deviates from the standard value, replace the sensor. (See Gr14.)

#764 Inspection of glow plug

* Measure the resistance value of glow plug as shown.

* If the measured value deviates from the standard value, replace the glow plug. (See Gr11.)

#930 Starter

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* Before removing the starter, disconnect the (-) battery cable and insulate the cable and the (-) battery terminal with tape. * It is dangerous to leave the (-) battery cable connected since the battery cable is always present at terminal B.

Disassembly Sequence

1 Stopper ring

2 Pinion stopper

3 Pinion

4 Spring

5 Magnetic switch

6 Rear bracket

7 Brush spring

8 Brush (-)

9 Brush holder

10 Brush (+)

11 Yoke

12 Rear bearing

13 Washer

14 Armature

15 Ball

16 Cover

17 Rubber packing

18 Planetary gear

19 Rubber packing

20 Plate

21 E-ring

22 Gear shaft

23 Washer

24 Internal gear

25 Overrunning clutch

26 Lever

27 Front bearing

28 Oil seal

29 Front bracket

X: Non-reusable parts

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* When the armature is removed, the ball may come out with it. Take care not to lose the ball.

* Do not remove the rear and front bearing unless defects are evident.

* It is not necessary to remove the pinion when only the motor section needs to be disassembled for inspection, like when inspecting brushes and related parts.

* Be sure to remove the pinion before disassembling any other parts.

Assembly Sequence

Follow the disassembly sequence in reverse.

* Whenever the magnetic switch is replaced, the pinion gap must be adjusted.

* The rubber packing is serviceable if any defect is not found.

Service Standards (Unit: mm)

Lubricant and/or Sealant

Special Tools

Work Before Disassembly

Mating Mark: Rear bracket and yoke

Disassembly Procedure

Disassembly: Pinion

* For removal of the pinion, the current must be supplied to the starter such that the pinion springs out.

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* When the starter is energized, the pinion will spring out and rotate. Be careful not to touch it with your hands. * The magnetic switch may become very hot during inspections. Be careful when touching it.

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* Do not energize the pull-in coil P for longer than 10 seconds, and do not energize the holding coil H for longer than 30 seconds. If these periods are exceeded, the coils may overheat and burn out. * To make the pinion spring out, be sure to energize the starter such that its parts are positioned correctly. If the starter is not energize and the lever is pulled to make the pinion come out, the front bracket and/or lever may be damaged by the shock inflicted upon them when the stopper ring is removed. * When current is supplied to the starter, a large current (100 A or higher) will flow. For inspection purposes, use booster cables or similarly thick cables. It is also important to ensure that all connections are secure.

* Connect the starter as illustrated.

* The following operations are performed with current supplied to the starter. Thus, the entire procedure for removal of the pinion must be completed within 30 seconds.

* Turn ON switches 1 and 2 to supply current to the starter. The pinion will spring out and rotate.

* After the pinion starts to rotate, quickly (within 5 seconds) turn OFF switch 2 to stop the pinions rotation.

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* When switches 1 and 2 are turned ON, the pull-in coil P and holding coil H are both energized. The circuit is connected such that no voltage is applied to starter terminal B, so current flows to the pull-in coil while the pinion rotates. To prevent the pull-in coil from burning out, it is essential to turn OFF switch 2 quickly (within 5 seconds) after the pinion starts to rotate.

* Apply a pipe-shaped implement to the pinion stopper.

* Using a hammer, lightly tap the pipe-shaped implement to remove the stopper ring from the ring groove of the pinion stopper.

* Remove stopper ring and pinion.

* Turn OFF switch 1 to de-energize the starter.

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* When the starter is de-energized, the mechanism will attempt to pull in the pinion. Thus, the stopper ring may slip back into the groove of the pinion stopper. If thus happens, energize the starter and go through the pinion removal procedure again.

Disassembly: Yoke and brush holder

* Use the following method to remove the yoke and brush holder in order to prevent the commutator of the armature from being damaged by the brushes.

* Lift the brushes away from the commutator and hold them lifted by applying the brush springs against the sides of the brush springs.

* Pull part A of each brush spring and pull up the brushes.

* Hold the brushes in position with the brush springs as illustrated.

* Remove the yoke and the brush holder.

Disassembly: Gear Shaft And Internal Gear

* Remove the E-rings and then the gear shaft and internal gear from the overrunning clutch. Proceed as follows if the gear shaft cannot be removed due to interference of the splined section of gear shaft with internal parts of the overrunning clutch.

* Press the gear shaft against the overrunning clutch.

* Turn the gear shaft approx. 1/8 of a turn to change the position of the splined section.

Disassembly: Front Bearing

Inspection Procedure

Inspection: Magnetic Switch

* Perform the following checks, and if any fault is found, replace the switch.

(1) Test for coil open circuit

* Check that continuity exits between terminals S and M.

* Check that continuity exits between terminal M and the body

(2) Test for fused-together contacts

* Check that continuity exits between terminals B and M.

(3) Test for contact-to-contact continuity

* Push in the end of the magnetic switch to close the internal contacts. Then, check that continuity exits between terminals B and M.

Inspection: Brush Spring Pressure

* Using new brushes, measure the load required to separate each brush spring from its brush.

* If either measurement is lower than the specified limit, replace the brush springs.

Inspection: Brush (-)

(1) Brush Length

* If either brush (-) is shorter than the limit, it must be replaced.

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* Brush (-) must be replaced together with the brush holder.

(2) Armature commutator contact surface of brush.

* If the commutator contact surface of either brush is rough or unevenly worn, rectify it with emery paper (#300 to 500).

Inspection: Brush Holder

* Thoroughly clean the (+) brush holder and the (-) holder plate, then, recheck that continuity does not exist between them.

* If continuity exists, there is a short circuit and the brush holder must be replaced.

Inspection: Yoke

(1) Test for coil open circuit

* Check that continuity exists between the cable and the (+) brush.

* If there is no continuity, there is an open circuit and the yoke or (+) brush must be replaced.

(2) Test for coil grounding

* Check that continuity does not exist between the yoke and the (+) brush.

* If continuity exists, the coil is grounded. Inspect the insulation, and replace the yoke and the (+) brush if the insulation cannot be rectified.

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* The coil may be grounded to the yoke due to the accumulation of worn-off metal particles from the brushes and/or armature.

Inspection: Brush (+)

(1) Brush Length

* If either brush (+) is shorter than the limit, it must be replaced.

(2) Armature commutator contact surface of brush

* If the commutator contact surface of either brush is rough or unevenly worn, rectify it with emery paper (#300 to 500).

Inspection: Armature

(1) Test for coil short circuit

* Hold an iron rod parallel with the armature.

* Slowly rotate the armature by hand.

* If the iron rod vibrates or is pulled toward the armature, the coil is short-circuited and the armature must be replaced.

(2) Test for coil grounding

* Check that continuity does not exist between the commutator and the core (or shaft).

* If continuity exists, the coil is grounded and the armature must be replaced.

(3) Commutator outside diameter

* If the measurement is out of specification, replace the armature.

(4) Runout of commutator periphery

* If the reading exceeds the specified limit, rectify the commutator of the armature, making sure the outside diameter stays within specification.

(5) Condition of commutator surface

* If the surface is rough or has stepped wear, rectify it with emery paper (#300 to 500).

* After rectifying the surface, check the extent of commutator runout.

(6) Mold depth between segments

* If the measurement is lower than the specified limit, rectify or replace the armature.

* To rectify the armature, grind the illustrated portions.

* If the mold is worn as illustrated, rectify or replace the armature.

O: Acceptable

X: Unacceptable

Inspection: Overrunning Clutch

* If the following inspections reveal any abnormality, replace the overrunning clutch.

* Turn the shaft in direction B and check that it rotates smoothly.

* Turn the shaft in direction A and check that it locks.

Assembly Procedure

Assembly: Front bearing

* Press-fit the front bearing
-A and
-B.

* After the press fitting, caulk the front bearing using the claws on
-A.

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* Avoid re-caulking previously caulked points.

Assembly: Yoke and brush holder

* To install the yoke and brush holder, follow the removal sequence in reverse. (See " Disassembly: Yoke and brush holder".)

Assembly: Magnetic switch

* Fit the magnetic switch onto the lever with terminal S aligned as illustrated.

Assembly: Pinion

* For installation of the pinion, it is not necessary to supply current to the starter.

* Fit the pinion stopper and pinion onto the overrunning clutch, making sure they are oriented as illustrated.

* Fit the stopper ring into the groove of the overrunning clutch.

* Pull the pinion hard and securely fit the stopper ring into the ring groove of the pinion stopper.

Inspection After Assembly

Inspection: Performance and pinion gap

* After assembling the starter, perform inspections with current supplied to it.

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* When the starter is energized, the pinion will spring out and rotate. Be careful not to touch it with your hands. * The magnetic switch may become very hot during inspections. Be careful when touching it.

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* Do not energize the pull-in coil P for longer than 10 seconds, and do not energize the holding coil H for longer than 30 seconds. If these periods are exceeded, the coils may overheat and burn out. * When current is supplied to the starter, a large current (100 A or higher) will flow. For inspection purposes, booster cables or similarly thick cables must therefore be used. Also, it is important to ensure that all connections are secure.

(1) Performance Test

* Connect the starter as illustrated.

* Set the voltage to 23 volts DC.

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* The voltage applied must not exceed 24 V.

* The following operations are performed with current supplied to the starter. Thus, the entire test (consisting of measurement of current flowing through the starter and measurement of the starter's rotational speed) must be completed within 30 seconds.

* Turn ON the switch to supply current to the starter. The pinion will spring out and rotate.

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* When the switch is turned ON, the pull-in coil P and holding coil H are both energized. When the large current from the DC power supply flows from terminal B to terminal M, the supply current to the pull-in coil P is cut; only holding coil H remains energized. To prevent the holding coil from burning out, it is essential to complete all operations within 30 seconds.

* Measure the current and the stator's rotational speed. To measure the rotational speed, shine a stroboscope on the pinion.

* Turn OFF the switch to de-energize the starter.

* If either measurement is out of specification, disassemble and inspect the starter again.

(2) Pinion Gap

* Connect the starter as illustrated.

* The following operations are performed with current supplied to the starter. Thus, the entire the entire procedure for measurement of the pinion gap must be completed within 30 seconds.

* Turn ON switches 1 and 2 to supply current to the starter. The pinion will spring out and rotate.

* After the pinion starts to rotate, quickly (within 5 seconds) turn OFF switch 2 to stop the pinions rotation.

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* When switches 1 and 2 are turned ON, the pull-in coil P and holding coil H are both energized. The circuit is connected such that no voltage is applied to starter terminal B, so current flows to the pull-in coil while the pinion rotates. To prevent the pull-in coil from burning out, it is essential to turn OFF switch 2 quickly (within 5 seconds) after the pinion starts to rotate.

* Pull out the end of the overrunning clutch and then lightly push in the end of the overrunning clutch and measure the amount of movement in the axial direction, i.e., the pinion gap.

* Turn OFF switch 1 to de-energize the starter.

* If the measurement is out of specification, replace the lever.

#940 Alternator

Removal Sequence

1 Adjusting bolt

2 Belts

3 Adjust plate

4 Alternator

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* Before removing the alternator, disconnect the (-) battery cable and insulate the cable and the (-) battery terminal with tape. * It is dangerous to leave the (-) battery cable connected since the battery cable is always present at terminal B.

Installation Sequence

Follow the removal sequence in reverse.

After installing the alternator, adjust the belt tension. (See Gr14.)

Service Standards

Inspection Procedure

Inspection: Alternator

(1) Alternator output current (bench test)

* Connect the alternator as illustrated.

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* Wires with sufficient thickness should be used for wiring and each connection should be securely fastened.

B: Terminal B

E: Terminal E

L: Terminal L

R: Terminal R

* Increase load resistance to the maximum (condition under which the load current hardly flows).

* Turn switch A and B ON

* Run alternator at 5000 rpm for 30 minutes by adjusting load resistance so that electric current can conform to the following standard.

* Measure the current at each specified revolution of alternator.

* If the measured value is lower than the standard value, disassemble and check alternator.

(2) Adjustment voltage of regulator (bench test)

* Connect the alternator as illustrated.

B: Terminal B

E: Terminal E

L: Terminal L

R: Terminal R

* Turn switch ON.

* Run alternator at low speeds.

* Increase the speed of alternator to 5000 rpm and measure the voltage (adjustment voltage) at this speed. at the same time, make sure that the current is 5 amperes or less at 5000 rpm.

* If the measured value deviates from the standard value, do as follows:

* If higher than the standard value: Replace the regulator.

* If lower than the standard value: Inspect the alternator related parts before replacing the regulator.

Disassembly Sequence

1 Pulley

2 Rear bearing

3 Rotor

4 Cover

5 Front bearing

6 Front bracket

7 Stator

8 Cover

9 Brush

10 Regulator and brush holder

11 Packing

12 Rectifier

13 Rear bracket

* Do not remove the rear and front bearing, stator, or brush unless faulty.

Assembly Sequence

Follow the disassembly sequence in reverse.

Service Standards (Unit: mm)

Tightening torque (Unit: N·m {kgf·m}

Disassembly Procedure

Disassembly: Rotor and front bracket

* Loosen the bolts retaining the front bracket and the rear bracket in position.

* Insert a screwdriver between front bracket and stator.

* Use the screwdriver to pry rotor and front bracket away from stator and rear bracket.

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* Be careful not to insert the screwdriver too deep or it will damage coil of stator and may cause a short-circuit.

Disassembly: Pulley

* Hold the rotor in a vise and loosen the nuts to remove the pulley.

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* Make sure to grip the root of the core claws when you hold the rotor vice. Gripping claws can damage them.

Disassembly: Rear bearing

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* Be careful not to damage slip ring when using the bearing puller. If the slip ring is damaged, the brush will not work efficiently.

Disassembly: Stator

* Disconnect lead of stator from rectifier. The lead is soldered to the diode of the rectifier at 3 places.

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* Unsolder within as short a time period as possible (within 5 seconds). Diode can be easily damaged by heat.

Disassembly: Brush

* After removing the cover, unsolder the leads of the brush and remove the brush from the regulator and brush holder.

Disassembly: Regulator and brush holder

* Melt the solder on points (at two points) of rectifier before removing regulator and brush holder.

Inspection Procedure

Inspection: Rotor

(1) Field coil resistance

* Measure the resistance between slip rings.

* If the measured value deviates from the standard value, replace rotor.

(2) Continuity between slip ring and core

* Check that there is no continuity between slip ring and core.

* If there is continuity, replace rotor since it has short-circuited.

(3) Outer diameter of slip ring

* If the outer diameter of slip ring is smaller than the limit, replace rotor.

* If the surface of slip ring is roughened or partially worn, polish the surface on a lathe or use emery paper.

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* Do not polish the surface to the point where the outer diameter of the slip ring becomes smaller than the limit.

Inspection: Stator

Perform the following check, and if any fault is found, replace the stator.

(1) Continuity between each lead wire

* Check that there is continuity between each stator lead.

* If there is no continuity, the lead has broken.

(2) Continuity between each lead wires and the core

* Check that there is no continuity between lead wires and the core.

* If there is continuity, the lead wire has short-circuited.

Inspection: Brush

* If the length of the brush has reached wear limit, replace the brush.

Inspection: Rectifier

* Check the function of diodes within rectifier properly. If any fault is found, replace the rectifier.

If resistance is infinite in both cases, the diode is open.

If resistance is close to 0 ohms in both cases, the diode is shorted.

A, B, C: Lead connecting area of stator coil

D, F: Heat sink area

E: Regulator connecting area

* Inspection should be conducted twice, changed over the positive probe and the negative probe of the tester.

* When inspecting using a tester, the current flowing through the rectifier is smaller than usual. Therefore, an incorrect resistance value may be indicated on the tester. Additionally, incorrect indications become larger as the range of the tester gets smaller. Set the tester to the largest possible scale.

Assembly Procedure

Assembly: Regulator and brush holder

* To install the regulator and brush holder, follow the disassembly sequence in reverse. (See " Disassembly: Regulator and brush holder".)

Assembly: Brush

* Install brush on regulator and brush holder in the direction as illustrated.

* After installation, solder the lead wire of brush on the regulator and brush holder. Thereafter, fit the cover as it was.

Assembly: Stator

* To install the stator, follow the disassembly sequence in reverse. (See " Disassembly: Stator".)

Assembly: Rotor and rear bracket

* If brush protrudes from regulator and brush holder, rotor cannot be installed onto the rear bracket. In this case, do the following:

* Push brush into regulator and brush holder.

* Insert pin into rear bracket from the rear to hold brush.

* After assembly, remove pin gently.

#950 Inspection Of Alternator

Performance Test

* The general inspection is only a simplified check. use a test bench for accurate checking.

* Connect the meters to the alternator as shown.

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* To prevent possible injury, be sure to disconnect the negative terminal of the battery and insulate it with tape before working on the wiring. With the negative (-) terminal of the battery connected, battery voltage is always applied to terminal B. * To connect to switch, use a lead wire with the same or larger diameter than that of the chassis harness connected to terminal B.

* Turn on switch and make sure that voltmeter indicates battery voltage.

* Start the engine.

* Immediately turn on the switches for all lamps on the vehicle.

* Immediately accelerate the engine to the speed indicated below and measure the alternator's output current. Approx. 2200 rpm

* The alternator is considered to be good if the measured value is 70% or more of the nominal output current.

Alternator Nominal Output

#951 Inspection Of Regulator

Service Standards

* Connect the meters to the alternator as shown.

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* To prevent possible injury, be sure to disconnect the negative terminal of the battery and insulate it with tape before working on the wiring. With the negative (-) terminal of the battery connected, battery voltage is always applied to terminal B. * To connect to switch, use a lead wire with the same or larger diameter than that of the chassis harness connected to terminal B.

* Turn off the switches for lamps, heater, etc. so that electric loads may not be applied during the inspection.

* Turn on switch and then start the engine.

* Start the engine.

* If the output current is 5 amperes or less when the engine speed is raised to the appropriate speed indicated below, then measure the voltage at terminal B. Approx. 2200 rpm

* If the output current is not less than 5 amperes, the measured value (regulated voltage) will be slightly lower.

* If the output current is 5 amperes or more, do one of the following:

* Run the engine for a while to charge the battery.

* Replace the battery with a fully-charged one.

* If the measured value deviates from the standard value, conduct checking again on the test bench.

#955 Inspection Of Preheating System

* Turn the starter switch to OFF.

* Connect a check lamp to the glow plug.

* If the check lamp does not turn on, inspect the glow plug.

* If any abnormality is found, replace the glow plug.

#959 Inspection Of Safety Relay

* Measure the output voltage at each terminal of the safety relay.

Service Standards

(1) Inspection of output voltage at terminal P

* Connect the voltmeter as shown in the drawing.

* Measure the voltage between the terminal P and the ground.

* If the measurement is out of specification, check the alternator and harnesses and replace any faulty part.

* Start the engine and run at idle (600 rpm or higher). Measure the voltage.

* If the measurement is 0V, the harness to the terminal P is short-circuited. Check the harness and connector and replace the faulty part.

(2) Inspection of output voltage at terminal R

* Connect the voltmeter as shown in the drawing.

* Set the starter switch to the AC position and measure the voltage.

* If the measurement is out of specification, check the harness and replace the faulty part.

(3) Inspection of output voltage at terminal S

* Connect two voltmeters and a pilot lamp as shown in the drawing.

* Set the starter switch to the START position and measure the voltage between terminal S and the ground during cranking.

* If the measurement is out of specification, faults at the following points are suspected. Check each point and replace the faulty part.

* If the measurement is near the battery voltage:

* Faulty safety relay

* If the measurement is 0V:

* Faulty harness

* Poor connection of connectors

* Faulty starter relay

* Faulty starter switch

* Start the engine and run at idle (600 rpm or higher).

* Measure the voltage at terminal P.

* If the measurement is out of specification, replace the alternator.

* Confirm that the pilot lamp does not turn on during idling. If the voltage at terminal P was normal but the pilot lamp turns on, replace the safety relay.

(4) Inspection of output voltage at terminal L

* Connect the voltmeter as shown in the drawing.

* Set the starter switch to the R1 or AC position and measure the voltage.

* If the measurement is out of specification, replace the safety relay. If the measurement is near the battery voltage, check the alternator and harness and replace the faulty part.