GM Buick/Oldsmobile/Pontiac/Full-Size 1975-1990 Repair Guide

Regulator

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The voltage regulator works with the battery and alternator to comprise the charging system. As the voltage regulator's name e implies, it regulates the voltage output of the alternator to a safe level (so the alternator does not overcharge the battery). A properly working regulator also prevents excessive voltage from burning out wiring, bulbs and other electrical components. All Buick, Olds and Pontiac models covered in this guide are equipped with integral regulators, which are built into the alternator case. The regulators are solid state and require no maintenance or adjustment.

REMOVAL & INSTALLATION



See Figures 1, 2 and 3

1975-1987 SI Series
  1. Remove the alternator from the vehicle. Position the assembly in a suitable holding fixture.
  2.  
  3. Make scribe marks on the case end frames to aid in reassembly.
  4.  
  5. Remove the through bolts. Separate the drive end frame assembly from the rectifier end frame assembly.
  6.  
  7. Remove the rectifier attaching nuts and the regulator attaching screws from the end frame assembly. Note the position of the screws with the insulated washers for reassembly.
  8.  
  9. Remove the voltage regulator from the end frame assembly.
  10.  

To install:
  1. Position the brushes in the brush holder and retain them in place using a brush retainer wire or equivalent.
  2.  
  3. Assemble the brush holder, regulator, resistor, diode trio and rectifier bridge to the end frame. Be sure to assemble the screws with the insulated washers in the correct locations.
  4.  
  5. Assemble the end frames together with the through bolts. Remove the brush retainer wire.
  6.  



Click image to see an enlarged view

Fig. Fig. 1: Regulator mounting on SI series alternators



Click image to see an enlarged view

Fig. Fig. 2: On all alternator models, the brushes can be retained with a wire in the holder

1987-1990 CS Series
TYPE 130
  1. Remove the alternator from the vehicle. Scribe marks on the end frames to facilitate assembly. Remove the through bolts and separate the end frames.
  2.  
  3. Remove the cover rivets or pins and remove the cover.
  4.  
  5. Unsolder the stator leads at the three terminals on the rectifier bridge. Avoid excessive heat, as damage to the assembly will occur. Remove the stator.
  6.  
  7. Remove the brush holder screw. Disconnect the terminal and remove the brush holder assembly.
  8.  
  9. Unsolder and pry open the terminal between the regulator and the rectifier bridge. Remove the terminal and the retaining screws. Remove the regulator and the rectifier bridge from the end frame.
  10.  

To install:
  1. Position the brushes in the brush holder and retain them in place using a brush retainer wire or equivalent.
  2.  
  3. Assembly is the reverse of disassembly. Be sure to remove the brush retainer wire when the alternator has been reassembled.
  4.  

TYPE 144
  1. Remove the alternator from the vehicle. Scribe marks on the end frames to facilitate assembly. Remove the through bolts and separate the end frames.
  2.  
  3. Remove the stator attaching nuts and the stator from the end frame.
  4.  
  5. Unsolder the connections, remove the retaining screws and connector from the end frame. Separate the regulator and brush holder from the end frame.
  6.  

To install:
  1. Position the brushes in the brush holder and retain them in place using a brush retainer wire or equivalent.
  2.  
  3. Assembly is the reverse of disassembly. Be sure to remove the brush retainer wire when the alternator has been reassembled.
  4.  



Click image to see an enlarged view

Fig. Fig. 3: Regulator mounting on CS series alternators

 
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