Renewing Alternator Brushes

How To Renew Alternator Brushes?

Modern vehicles use alternators to recharge the battery and power other electrical components. They are more effective than dynamos since they produce more power and offer your battery faster and better recharging speeds. After some time, however, the alternator will wear out, and you have to repair it. One of the most common problems is with the alternator brushes. Renewing alternator brushes is crucial for the best performance of your alternator.

Alternator brushes are made from graphite. It is a better power conductor and resists wear and tear for a long time. You can thus get good performance from this brush for over six years. The alternator brushes will reduce the wear on your commutator and ensure it performs well. The alternator brushes will suffer from the friction it generates with other vehicle components during their performance. Identifying problems with the alternator brushes ensures the direct current generated from the alternator reaches all electrical components and that the battery is fully charged.

What Causes Problems With The Alternator Brushes?

Problems with the alternator brushes are simple to identify. They reflect electrical problems in the vehicle, and you can thus begin correcting them. Additionally, if your battery runs flat after only a short time despite recharging, it shows the alternator brushes aren’t working well. Here are some of the problems that cause the alternator problems;

#1. Incorrect alternator brushes installation

When you install incorrect alternator brushes, they will not work well. These include wrong-sized brushes or those incorrect for your alternator model. It is thus a common problem and is simple to correct.

#2. Electrical overloading or underloading

The alternator brushes transmit direct current generated from the alternator to other electrical components. When you subject the brushes to overloading or underloading, they will wear out and thus become ineffective. Renewing alternator brushes when they wear out is vital.

#3. Underperforming commutators

When the alternator brushes wear out, it causes sparking in the commutator. It causes leakages in electrical current and thus interferes with alternator performance. Once you replace the alternator brushes, it performs well and prevents sparking.

Renewing Various Types Of Alternator Brushes

There are various types of alternator brushes, depending on your vehicle model. You should thus check the one on your vehicle before renewing. It ensures you have the right option and will, in turn, make installation simpler.

#1. Renewing Motorola Brushes

There is a common brush option available in modern vehicles. If your alternator isn’t performing well, renewing the Motorola brushes will correct the problem. Its brush box is located under the cover plate at the back of the alternator. The brushes are held in place by screws, making replacement easier. Firstly, take off the screws on the brush box and free it from its position. Do this carefully to prevent tagging on the cables inside the cover plate.

Additionally, you must note how all the components have been connected. Reinstalling them is a backward installation process, which ensures you can do it accurately. Open the screws holding the brushes in place. Remove them carefully and clean all the components. Finally, you can return all the components as they previously were. It will thus begin working as required.

#2. How To Renew Lucas AC Brushes

These are also common vehicle components in the alternator. Renewing these brushes is different from others. It will, however, need similarly high attention to detail. Firstly identify the brush box and, using a screwdriver, unscrew the bolts holding it in place. Use the screwdriver to remove the brushes installed in the spade terminals. Remove them carefully as these terminals will easily bend.

You can now wipe down the brush housing and the slip rings. Preventing more dirt accumulation will reduce wear and tear and ensure it works well. You can now reinstall the brushes after cleaning. Firstly, fit the spade terminals in place. Retain the tag lock by pulling them into position using the right tools. Once in place, you can fit the brush box. The replacement is complete, and you can test the new installation for proper performance.

#3. How To Renew Lucas ACR Brushes

If your vehicle uses Lucas ACR brushes, you can follow this guide for renewing alternator brushes. The procedures are different for all alternator brushes, and you should thus identify the one on your vehicle before you proceed. Firstly, remove the molded cover from the back of your alternator. Carefully open its recessed bolts using the correct size socket spanner.

Disconnect the cable connections to the brush terminal strip. It is vital to mark them during disassembly to make reconnection easier and more accurate. After this, loosen the bolts that hold the field link and remove it. You can now open the bolts holding the brush box and remove them.

It exposes the slip rings, and you can now clean them. You can now install the new one after removing all the components blocking the alternator brushes. Importantly, don’t damage the leaf spring in the inner brush during the disassemble and reassembly process. Finally, you can reassemble the components reverse from how you disassembled them. Insert the marked cables disconnected earlier into the right positions. Ensure that your installation is firmly in place to prevent future alternator brush problems.


When renewing alternator brushes, it is vital to get ones that will fit in well with your setup. Indeed, look through the manufacturer’s specifications to get the right one. An under or oversize alternator brush will wear out fast and fail to perform as effectively as a good one. They are thus an important component to get right. Handle all the components in your setup carefully as they are delicate. They will bend easily, and you will have to make bigger repairs.

During renewing, you can mark the cables disconnected to their correct ports. It will thus make reassembly simpler. Renewing the alternator brushes on your vehicle is now simpler. You don’t need to get a technician for the job.