Toyota Cressida and Van 1983-1990

Alternator

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ALTERNATOR PRECAUTIONS



Several precautions must be observed with alternator equipped vehicles to avoid damage to the unit.



If the battery is removed for any reason, make sure it is reconnected with the correct polarity. Reversing the battery connections may result in damage to the one-way rectifiers.
 
When utilizing a booster battery as a starting aid, always connect the positive to positive terminals and the negative terminal from the booster battery to a good engine ground on the vehicle being started.
 
Never use a fast charger as a booster to start vehicles.
 
Disconnect the battery cables when charging the battery with a fast charger.
 
Never attempt to polarize the alternator.
 
Do not use test lamps of more than 12 volts when checking diode continuity.
 
Do not short across or ground any of the alternator terminals.
 
The polarity of the battery, alternator and regulator must be matched and considered before making any electrical connections within the system.
 
Never separate the alternator on an open circuit. Make sure all connections within the circuit are clean and tight.
 
Disconnect the battery ground terminal when performing any service on electrical components.
 
Disconnect the battery if arc welding is to be done on the vehicle.
 

BELT TENSION ADJUSTMENT



Inspection and adjustment to the alternator drive belt should be performed every 3000 miles or if the alternator has been removed.

  1. Inspect the drive belt to see that it is not cracked or worn. Be sure that its surfaces are free of grease or oil.
  2.  
  3. Push down on the belt halfway between the fan and the alternator pulleys (or crankshaft pulley) with thumb pressure. Belt deflection should be 3 / 8 - 1 / 2 in. (10-12 mm).
  4.  
  5. If the belt tension requires adjustment, loosen the adjusting link bolt and move the alternator until the proper belt tension is obtained.
  6.  
  7. Do not overtighten the belt, as damage to the alternator bearings could result. Tighten the adjusting link bolt.
  8.  
  9. Drive the vehicle and re-check the belt tension. Adjust as necessary.
  10.  

INSPECTION





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Fig. Fig. 1 Checking the charging circuit



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Fig. Fig. 2 Grounding terminal F of the alternator

The following inspection is to be used to test the charging circuit without a load.

If a battery or alternator tester is available, connect the tester to the charging circuit as per manufacturer's instructions. If a tester is not available, connect a voltmeter and ammeter to the charging circuit as follows:

  1. Disconnect the wire from terminal B of the alternator and connect the negative probe of the ammeter to it.
  2.  
  3. Connect the test probe from the positive terminal of the ammeter to terminal B of the alternator.
  4.  
  5. Connect the positive probe of the voltmeter to terminal B of the alternator.
  6.  
  7. Ground the negative probe of the voltmeter.
  8.  
  9. Check the charging system as follows:
  10.  
    1. With the engine running at 2000 rpm, the reading on the ammeter and voltmeter should be 10 amps or less and 13.5-15.1 volts at 77°F (25°C).
    2.  
    3. If the voltage reading is greater than specified, replace the IC regulator.
    4.  
    5. If the voltage reading is less than specified, check the IC regulator and alternator as follows:
    6.  

  11. With terminal F grounded, start the engine and check the voltage reading of terminal B .
  12.  
  13. If the voltage reading is greater than the standard voltage, replace the IC regulator.
  14.  
  15. If the voltage reading is less than the standard voltage, check the alternator.
  16.  
  17. To check the charging circuit with a load, use the following test.
  18.  
    1. With the engine running at 2,000 rpm turn on the high beam headlights and place the heater fan control on HI.
    2.  
    3. Check the reading on the ammeter. The standard amperage reading is 30 amp or more.
    4.  
    5. If the ammeter reading is less than 30 amps, repair or replace the alternator as necessary.
    6.  


With the battery fully charged, the indications will sometimes be less than 30 amps. If an IC regulator is found to be faulty, it is recommended that the alternator be replaced with a new one or a rebuilt one, due to the complexity involved with disassembling the alternator in order to gain access to the regulator and then to reassemble the unit.

REMOVAL & INSTALLATION





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Fig. Fig. 3 Disconnect the wiring from the rear of the alternator



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Fig. Fig. 4 Loosen the alternators adjusting lock, pivot and adjusting bolts-1989-90 Cressida shown



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Fig. Fig. 5 Alternator mounting-4Y-EC engine



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Fig. Fig. 6 When removing the alternator, first remove its drive belt and any belts that are in the way-Van shown



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Fig. Fig. 7 Loosen and remove the alternator mounting bolts



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Fig. Fig. 8 Move the alternator from the engine far enough so ...



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Fig. Fig. 9 ... you can separate the wiring from the alternator



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Fig. Fig. 10 Now you can remove the alternator completely

On some vehicles, the alternator is mounted very low on the engine. On these vehicles it may be necessary to remove the gravel shield and work from underneath the vehicle in order to gain access to the alternator.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner, if necessary, to gain access to the alternator.
  4.  
  5. Remove the power steering or air conditioning drive belts, as required.
  6.  
  7. Unfasten the bolts which attach the adjusting link to the alternator. Remove the alternator drive belt.
  8.  
  9. Unfasten and tag the alternator attaching bolt and then withdraw the alternator from its bracket.
  10.  
  11. Installation is the reverse of the removal procedure. After installing the alternator, adjust the belt tension.
  12.  

 
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