How To Rebuild an Alternator

Your car's alternator is basically a generator, which your engine uses to supply electricity to the car and charge the car's battery while the engine is running. This mechanical energy is generated through the use of a conveyor belt. When the belt produces enough mechanical energy, the alternator transforms it into electrical energy so that the battery car can use it. In most older cars, the alternator is one of the first components to fail, since a car usually requires a certain voltage in order to operate properly. When the alternator no longer generates enough voltage, it takes a toll on the battery, which could subsequently fail.

If you feel competent enough to rebuild your alternator, here are a few tips in removal, rebuilding and replacement.

What you need

  1. Set of drive sockets (1/4 inches and 1/2 inches)
  2. Screwdrivers (Phillips and Flat)
  3. Paper clip
  4. Small gear puller
  5. Heat sink compound
  6. Alternator rebuild kit
  7. Sandpaper
  8. Pen and paper

What to do

  1. For safety purposes, disconnect the car battery before doing any work on the electricals. Once done, look for the alternator and familiarize yourself with how the wires are connected to the device. For reference with rewiring, draw the wiring scheme of the device with your pen and paper.
  2. The alternator is fixed by two bolts. One attaches the alternator to the engine block, and the other is used to adjust tightness. Remove both of the bolts and spacers then carefully remove the alternator. Mark a straight line on the two halves of the case. This mark will guide you for reassembling the device later.
  3. You will see the three bolts that hold the case together. Remove these bolts so you can open the device. After removing the bolts, carefully pry the casing apart. Once opened, you will most likely see dirt and grime inside the alternator. Clean all of these out.
  4. In the first half of the device case, you will see three screws that hold the stator to the diodes. Remove these screws and remove the stator windings.
  5. Automobile alternatorLocate the white voltage regulator. When you see it, remove the three screws that hold it attached to the assembly. Then, remove the black, rectangular diodes. Carefully remove the brush holder and the voltage regulator.
  6. At the front of the alternator, you will find the pulley nut, lock washer and the fan. Remove all of these using small pliers.
  7. When all of the parts are already removed, remove the rotor from the case and the bearing. The bearing can be removed by carefully pushing it out. In the same way, remove the needle bearing on the rear part of the device. Place the new bearings from the outside in.
  8. Cover the rear portion of the new voltage regulator with an even layer of heat sink compound. Put in the new voltage regulator, brushes and diodes and replace the three screws on the voltage regulator. Replace the stator and the three bolts in the diodes with new ones.
  9. With a wet/dry sand paper, clean the slip-rings of the rotor. Slip a paper clip from outside of the case into the hole that goes through the brush holder. Push the brushes against the springs and push the paper clip so that it holds the brushes.
  10. Replace the rotor in the front of the case. Replace the fan, pulley, washer and nut. Get the two case halves and put them together. Install the rear rotor shaft into the rear bearing. Replace the three bolts that hold the case halves together and try to spin the rotor and check if it spins freely.
  11. You can now return the alternator to its proper place in the engine bay. Reconnect the wires according to the correct wiring scheme you previously noted. Then, tighten the belt onto the pulley.

Rebuilding a car alternator has two major benefits. First, it saves you money from buying a brand new one. Second, doing it yourself can help you familiarize yourself with the electrical components of your car. This way, you will find it easier to troubleshoot the next time you experience poor engine performance, or even a dead battery.


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