How to Change an Alternator
You can learnhow to replace the alternatorin your car in a few minutes and, depending on your particular vehicle make and model, perform this repair in about an hour. All you need is some common tools. However, you don't need special knowledge or technical skills. Perhaps, the best part is that this job is not complicated, if you follow a proper guide. At the end, you will have gained some knowledge in car repairs and saved in repair expenses as well.
1. Removing the alternator
At this point, it is a good idea to check whether you will be removing the alternator from the top or bottom of the engine compartment. This will depend on the space available to get access to the unit. If you have to, raise the front of your car now using a jack and secure it with a couple of jack stands so that you are ready to remove the alternator. Then, make a note of the path the alternator belt follows around the pulleys so that you reinstall it correctly.Now, you are almost ready to begin your repair. Before you start though, cut power to the engine.Disconnect the batteryby detaching the negative battery cable. This will prevent an electrical charge from damaging other components as you work on your alternator. The negative cable is the thick, black wire attached to the battery post with the negative (-) mark next to it. Make sure to isolate the terminal from the battery post after removing the cable to prevent the terminal from accidentally touching the post.To remove theserpentine beltoff the alternator, locate and rotate the belt tensioner pulley using a large wrench or a breaker bar. This will relieve the belt tension and allow you to slip the belt off the alternator pulley. If your vehicle has more than one accessory belt, you will need to loosen the locking and pivot bolts or nut on your alternator first. You can use a wrench and a ratchet and socket for this. Some alternators, though, have a third bolt to secure the alternator in place or to adjust the belt. Once you have loosened the alternator bolts, move the alternator towards the engine side to remove belt tension. Then you can slip the belt off the alternator pulley.Before you pull out the alternator, unplug all the electrical connectors from the back of the alternator. Pay special attention to the way the electrical connectors lock onto their fittings. Now you can remove the alternator mounting and adjusting bolts. When ready, carefully pull the alternator out of the engine.2. Getting the correct alternator for your vehicleWith the alternator out of the vehicle, you may choose to send the unit to an electrical shop for diagnosis, have them rebuild it, or buy a rebuilt or brand new one. If you decide to get a replacement, take your old unit to the auto parts store so that you can compare the number of electrical connectors, their location around the back of the housing, and their configuration. They all have to match on the new alternator. Also, compare the code markings on the old alternator with those on the new unit. They have to match. Finally, make sure the new alternator has the same configuration and placement of the mounting holes to make sure you are buying the correct alternator for your particular vehicle make and model.3. Installing the alternatorPlace the new alternator in its mounting position in the engine compartment, plug in all the electrical connectors and install the mounting bolts, but do not tighten them yet, unless your car comes equipped with a serpentine belt. Also, slip the alternator belt over the alternator pulley. Pull the unit away from the engine to tension the belt using a prying bar or breaker bar. Some alternators come with a square hole in one of its mounting brackets, so that you can use a breaker bar for this purpose.It is a good idea to ask a helper to tighten the bolts as you hold the alternator in position to provide the proper tension to the belt. If your vehicle comes with a serpentine belt, rotate the belt tensioner pulley and slip the belt over the alternator pulley. Slowly release the tensioner. Double check your installation and make sure the belt is routed correctly. Then, reconnect the negative battery cable.Following the proper procedure, you can learn how to replace the alternator in a few minutes. On some vehicle models, though, it may take you more than a few minutes, if you need to remove other components to gain access to the alternator. In this case, you can buy the service manual for your particular vehicle make and model from an auto parts store or consult one for free in your local public library. This will guide you in removing other components and getting ready to make a successful car repair at home.
