Jeep CJ/Scrambler 1971-1986 Repair Guide



See Figures 1, 2 and 3


To prevent damage to the alternator and regulator, the following precautionary measures must be taken when working with the electrical system.

  1. Never reverse battery connections. Always check the battery polarity visually. This is to be done before any connections are made to be sure that all of the connections correspond to the battery ground polarity of the Jeep.
  3. Booster batteries for starting must be connected properly. Make sure that the positive cable of the booster battery is connected to the positive terminal of the battery that is getting the boost. This applies to both negative and ground cables.
  5. Disconnect the battery cables before using a fast charger. The charger has a tendency to force current through the diodes in the opposite direction for which they were designed. This burns out the diodes.
  7. Never use a fast charger as a booster for starting the vehicle.
  9. Never disconnect the voltage regulator while the engine is running.
  11. Do not ground the alternator output terminal.
  13. Do not operate the alternator on an open circuit with the field energized.
  15. Do not attempt to polarize an alternator.


  1. Remove all of the electrical connections from the alternator or generator. Label all of the wires so that you can install them correctly.
  3. Remove all of the attaching nuts, bolts and washers noting different sized threads or nuts and bolts that go in certain holes.
  5. Remove the alternator carefully.
  7. To install, reverse the above procedure and adjust the belt as described below. Torque the mounting bolts to 25-30 ft. lbs.; the sliding adjuster bolt to 20 ft. lbs.

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Fig. Fig. 1: Remove the alternator bracket mounting bolt

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Fig. Fig. 2: Remove the top alternator mounting bolt and this spacer

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Fig. Fig. 3: Be sure that wires are disconnected and then remove the alternator


The fan belt drives the generator/alternator and the water pump. If it is too loose, it will slip and the generator/alternator will not be able to produce the rated current. if the belt is too loose, the water pump would not be driven and the engine could overheat. Check the tension of the fan belt by pushing your thumb down on the longest span of belt midway between the pulleys. If the belt flexes more than 1 / 2 in. (13mm), it should be tightened. Loosen the bolt on the adjusting bracket and pivot bolt and move the alternator or generator away from the engine to tighten the belt. Do not apply pressure to the rear of the case aluminum housing of an alternator; it might break. Tighten the adjusting bolts when the proper tension is reached. See General Information & Maintenance of this guide for more information.