GM Full-Size Trucks 1970-1979 Repair Guide

Alternator

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Three basic alternators are used; the 5.5" series ID Delcotron, the 6.2" series 150 Delcotron and the integral regulator 10 SI Delcotron.

ALTERNATOR PRECAUTIONS





When installing a battery, ensure that the ground polarity of the battery, the alternator and the regulator are the same.
 
When connecting a jumper battery, be certain that the correct terminals are connected.
 
When charging, connect the correct charger leads to the battery terminals.
 
Never operate the alternator on an open circuit. Be sure that all connections in the charging circuit are tight.
 
Do not short across or ground any of the terminals on the alternator or regulator.
 
Never polarize an AC system.
 

REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4, 5, 6, 7, 8 and 9



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Fig. Fig. 1: Tag and detach the electrical connector from the back of the alternator



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Fig. Fig. 2: Unfasten the battery lead retaining nut ...



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Fig. Fig. 3: ... then remove the battery lead from the alternator



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Fig. Fig. 4: Remove the alternator brace bolt



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Fig. Fig. 5: Remove the drive belt(s)



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Fig. Fig. 6: Unfasten the alternator mounting bolts ...



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Fig. Fig. 7: ... then remove the alternator from the vehicle



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Fig. Fig. 8: View of a common inline 6-cylinder engine alternator mounting



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Fig. Fig. 9: Alternator mounting and retainer locations - 8-cylinder engines

  1. Disconnect the battery ground cable.
  2.  
  3. Disconnect and tag all wiring to the alternator.
  4.  
  5. Remove the alternator brace bolt. If the truck is equipped with power steering, loosen the pump brace and mount nuts.
  6.  
  7. Remove the drive belt(s).
  8.  
  9. Support the alternator and remove the mounting bolts. Remove the alternator from the truck.
  10.  
  11. Installation is the reverse of removal. Adjust the belt(s) to have 1 / 4 - 1 / 2 in. depression under thumb pressure on its longest run.
  12.  

 
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