Change the Alternator in your Car
You don't need special skills tochange the alternatorin your vehicle, but you do need to know how to prevent damage to components during the process and guarantee that the charging system in your car will operate as it should. Depending on your particular vehicle, you can change the alternator in a few easy steps or follow a more involved process. Still, you can replace your vehicle's alternator at home using a few common tools you may already have.
Removing the alternator
Before you start,disconnect the negative terminalfrom the battery using a wrench. This will prevent a potential short circuit from damaging electrical or electronic components as you work on your alternator. Now, check whether you have enough room to remove the alternator from the top of the engine compartment. This will depend on the distribution of accessories around the engine.
Don't feel discouraged if you don't see a way to remove the alternator from the top. You'll probably have to work through the bottom of the engine compartment. See if you need to remove a splash shield from under the engine compartment. Use a floor jack to raise your vehicle and support it safely on jack stands. Then, block the rear wheels and engage the parking brake before crawling under the car. Once you remove the shield, reach for the alternator's mounting bolts and bracket.
Start loosening the adjusting, pivot and/or holding alternator's bolts. This will let youremove the drive beltif your alternator has one.
Vehicle models with a serpentine belt offer a more friendly way to remove—and reinstall—the belt. To remove it, rotate the spring-loaded belt tensioner against the spring force (by placing a wrench or socket wrench on the tensioner's bolt). This will release belt tension, allowing you to slip the belt off the alternator's pulleys. Then, slowly let the tensioner pulley spring back into place.
After removing the drive or serpentine belt, unplug all electrical connections from the alternator's back. Note which connection/wire connects where, so that you install each one back in the correct place. Then, remove the bolts and alternator from your vehicle.
Installing the alternator
To install the alternator, follow the same removal process in reverse order. If your alternator has a drive belt, though, you'll need to manually adjust the belt tension while installing it. Do it before tightening the locking and pivot bolts that secure the alternator in place.
After connecting and plugging in all the connectors and wires to the back of the alternator (leave the mounting bolts loose), move the alternator away from the engine to tense the belt. On some alternators, the mounting bracket comes with a square hole, so you can use a 1/2-inch square drive breaker bar for this purpose; otherwise, use a pry bar to push the alternator as you adjust the belt, being careful with the accessories around it to prevent damage.
Keeping the belt tense, press on the belt's middle section—between two of the pulleys with the longest stretch-—using your thumb. The belt should deflect 1/8 to a 1/4 of an inch, if the distance between the pulleys is 12 inches or less; or 1/8 to a 3/8 of an inch, if the distance between the pulleys is more than 12 inches. Once the belt has the correct tension, tighten the bolts and reconnect the battery negative terminal.
When changing your vehicle's alternator, remember to work in a safe manner to prevent personal injuries and damage to other components. If necessary, read the instructions in your repair or service manual for your particular make/model/year vehicle. The manual will help you solve any difficulties you may encounter while replacing the alternator. If you don't own or want to buy the manual, you may consult it in the reference section of your local public library.
