DIY Basic Alternator Repair Guide

The alternator of your car is a device that is responsible for converting the mechanical energy produced by the engine into electrical energy that mainly charges the battery.  Just like any other part of your vehicle, the alternator undergoes wear and tear. By regularly servicing alternators, it is possible to increase the lifespan of your car’s alternator.

Preventive service of the alternator is important because replacing them is expensive. However, if your alternator has just given up on you, don’t start looking for a new one just yet.

Many times, the whole alternator is not damaged and only the brushes and regulators are damaged. In the following sections, we will be discussing how you can diagnose if the brushes of your alternator have worn out and how you can replace the brushes and avoid buying a new alternator.

DIY Basic Alternator Repair Guide

Diagnosing Alternator Problems

If your vehicle’s battery is not charging properly, it is an indication that something might be wrong with your alternator.

To check if there is something wrong with your alternator, begin by checking if the alternator is sending enough voltage to the battery. To do this, simply put your car in ignition and while the engine is running, check the voltage in the wire with a voltmeter. Compare this with the recommended voltage mentioned in the user manual of your car. If it’s lower, then your alternator is the culprit.

If this is the case, you may need to take your alternator out of the engine bay for further inspection. To do this, begin by taking pictures of all the hinges, screws and wire connections associated with the alternator. This way, you can refer to these pictures when you need to reconnect it again.

Pro tip: Always make sure you disconnect the battery before removing the alternator. To do this, simply locate the negative (-) terminal on the battery, unscrew the wire bolt and disconnect the wire.

After you have removed the alternator, it is time to remove the rear plastic cover. Once you do that, you will be able to see the regulator and the brushes

Take a photograph (like the one above) of the whole setup before you remove the brushes and the regulator. Check the brushes for damage and wear and tear. If you noticed that the brushes’ length has been shortened due to wear and tear, you have successfully diagnosed the problem.

Replacing The Brushes Of Car Alternator

Replacing the brushes of your car’s alternator is as easy as it was to remove the old, damaged ones. All you will need to do is order a brush and regulator replacement kit specific to your car’s make and model. While the exact price will vary for different cars, most brush and regulator replacement kits average around the $30 mark.

Once you have replaced the alternator’s brushes and regulator, reconnect the alternator to the battery and fix it in the engine bay. Then reconnect the battery and try putting your car in ignition. When the engine is running, check the voltage of the current flowing from the alternator to the battery, it should be close to the ideal voltage described in your car’s manual.


While a worn out brush and regulator is a small alternator issue, it can cause more serious damage to the alternator if left unchecked. Hence, it is a good idea to add checking the brush and regulator for wear and tear when you are performing preventive maintenance on your car’s alternator.

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