GM Cutlass RWD 1970-1987 Repair Guide

Alternator

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See Figure 1

The alternating current generator (alternator) supplies a continuous output of electrical energy at all engine speeds. The belt-driven alternator generates electrical energy and recharges the battery by supplying it with electrical current. The alternator consists of four main assemblies; two end frame assemblies, a stator assembly, and a rotor assembly. The rotor assembly is supported in the drive end frame by a ball bearing and at the other end by a roller bearing. These bearings are permanently lubricated and require no maintenance. There are six diodes in the end frame assembly. These diodes are electrical check valves that also change the alternating current developed within the stator windings to direct current (DC) at the output (BAT) terminal. Three of these diodes are negative and are mounted flush with the end frame while the other three are positive and are mounted into a component called a heat sink (which serves as a reservoir for excess heat, thus protecting the alternator). The positive diodes are easily identified as the ones within small cavities or depressions.

No periodic adjustments or maintenance of any kind, except for regular belt adjustments, are required on the entire alternator assembly. Alternator output in amps, is sometimes stamped on the case of each unit, near the mounting hole. Regulator voltages range between 13.6 and 16 volts at 75°F.



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Fig. Fig. 1: Charging circuit system

ALTERNATOR PRECAUTIONS




WARNING
To prevent serious damage to the alternator and the rest of the charging system, the following precautions must be observed:

  1. Always observe proper polarity of the battery connections; be especially careful when jump-starting the car.
  2.  
  3. Never ground or short out any alternator or alternator regulator terminals.
  4.  
  5. Never operate the alternator with any of its or the battery's leads disconnected.
  6.  
  7. Always remove the battery or disconnect its output lead while charging it.
  8.  
  9. Always disconnect the battery ground cable when replacing any electrical component.
  10.  
  11. Never subject the alternator to excessive heat or dampness. If you are steam-cleaning the engine, cover the alternator.
  12.  
  13. Never use arc-welding equipment with the alternator connected.
  14.  

ALTERNATOR TESTING



See Figures 2 and 3

Two types of alternator/regulator combinations have been used on the Cutlass. From 1970-72, an alternator with external regulator was used on Standard Cutlasses. 1973 and later models use an alternator with the regulator incorporated. 4-4-2 models have used the integral regulator alternator since 1970. While several charging system tests are given here, alternator repair procedures are not. Because of their complexity, it is recommended that you take your alternator to a qualified rebuilder if it is defective.

Preliminary Charging System Tests

If you suspect a defect in your charging system, first perform these general checks before going on to more specific tests.

  1. Check the condition of the alternator belt and tighten if necessary.
  2.  
  3. Clean the battery cable connections at the battery. Make sure the connections between the battery wires and the battery clamps are good. Reconnect the negative terminal only and proceed to the next step.
  4.  
  5. With the key off, insert a test light between the positive terminal on the battery terminal clamp. If the test light comes on, there is a short in the electrical system of the vehicle. The short must be repaired before proceeding. If the light does not come on, then proceed to the next step.
  6.  

If the vehicle is equipped with an electric clock, the clock must be disconnected.

  1. Check the charging system wiring for any obvious breaks or shorts.
  2.  
  3. Check the battery to make sure it is fully charged and in good condition.
  4.  

Alternator Output Test
ALTERNATOR WITH EXTERNAL REGULATOR

You will need a tachometer and a voltmeter for this test. You will also need a jumper wire.

  1. Connect the tachometer to the engine.
  2.  
  3. Disconnect the wiring harness at the voltage regulator. With a jumper wire, connect the F : wire to the number three wire in the wire harness plug.
  4.  
  5. Connect a voltmeter across the battery terminals, the positive voltmeter lead to the positive battery terminal and the negative lead to the negative terminal. Note the reading.
  6.  
  7. Start the engine and let it idle.
  8.  
  9. Gradually raise the engine speed to 1500-2000 rpm. The reading on the voltmeter should increase one to two volts over the initial reading. If there is no increase in the reading, the alternator is defective and must be repaired, If the increase is greater than two volts, then the regulator is defective and must be adjusted or replaced. (See voltage adjustment in the regulator section).
  10.  

ALTERNATOR WITH INTEGRAL REGULATOR

You will need a ammeter for this test.

  1. Disconnect the battery ground cable.
  2.  
  3. Disconnect the wire from the battery terminal on the alternator.
  4.  



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Fig. Fig. 2: Common alternator mounting Buick built engines

  1. Connect the ammeter negative lead to the battery terminal wire, and connect the ammeter positive lead to the battery terminal on the alternator.
  2.  
  3. Reconnect the battery ground cable and turn on all electrical accessories. If the battery is fully charged, disconnect the coil wire and bump the starter a few times to partially discharge it.
  4.  
  5. Reconnect the coil wire. Start the engine and run it until you obtain a maximum current reading on the ammeter.
  6.  
  7. If the current is within ten amps of the rated output of the alternator, the alternator is working properly. If the current is not within ten amps, insert a screwdriver in the test hole in the end frame of the alternator and ground the tab in the test hole against the side of the hole.
  8.  
  9. If the current is now within ten amps of the rated output, remove the alternator and have the voltage regulator replaced. If it is still below ten amps of rated output, have the alternator repaired.
  10.  



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Fig. Fig. 3: Common alternator mounting Chevrolet built engines

REMOVAL & INSTALLATION



See Figures 4, 5 and 6

  1. Disconnect the battery ground cable.
  2.  
  3. L6 engines have their alternators mounted on the left side. V8 engines have their alternator mounted high on the right-hand side, unless. V6 alternators are mounted on the right-hand side.
  4.  
  5. Disconnect all wiring to the alternator, noting the locations of the wires. You may find it helpful to mark the wires.
  6.  
  7. Loosen the alternator adjusting bolt and slide the alternator over until you can remove the drive belt. On cars equipped with air-conditioning and/or power steering, it may be necessary to loosen one or the other to gain access to the alternator. If addition, it is sometimes far easier to work from underneath the car.
  8.  
  9. Remove the alternator mounting bolts and remove the alternator.
  10.  
  11. Installation is the reverse order of removal. When adjusting the belts, make sure you have 1 / 4 in.- 1 / 2 in. of play at the belt's mid-point.
  12.  



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Fig. Fig. 4: Disengage all electrical connections from the alternator



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Fig. Fig. 5: Remove the alternator mounting bolts



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Fig. Fig. 6: Remove the alternator once the belt is off and all the bolts/wiring are disconnected

 
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