Download ArticleDownload ArticleThis article was co-authored by Duston Maynes. Duston Maynes is an Automotive Repair Specialist at RepairSmith. Duston specializes in leading a team that handles a variety of automotive repairs including replacing spark plugs, front and rear brake pads, fuel pumps, car batteries, alternators, timing belts, and starter motors. Duston holds an Associate’s degree in Automotive/Diesel Technology from The Universal Technical Institute of Arizona and is a Certified Diagnostic Technician and Automobile Mechanics Technician through BMW STEP. RepairSmith received The 2020 Big Innovation Award by Business Intelligence Group and The Startup of the Year by the American Business Awards. RepairSmith was also included in Built in LA’s 50 Startups to Watch and The Business Intelligence Group’s 52 Names Leading the Way in Customer Service. RepairSmith offers in-home services to provide car owners convenient and complete auto repair everywhere.
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Even maintenance-free car batteries can acquire corrosive buildup, which is produced when hydrogen gas produced by the battery comes into contact with dirt and sediment on the surface of the battery. Removing the terminals and cleaning them will help to prevent future mechanical problems.
Disconnecting Car Battery Terminals
Make sure the positive terminal's cover is on or place a towel over it. Loosen the nut on the negative terminal with a socket wrench and lift the terminal off the battery post. Remove the cover from the positive terminal, loosen the nut, and lift the terminal off the post.
Steps
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Open the hood of the car and use the support bar to prop it open.[1]
Locate the battery within the engine compartment. If you're unsure about which part is the battery, then check your owner’s manual. Some vehicles have their battery in the trunk, under or behind an access panel.Advertisement
Check the positive post to be sure that the cover is on. If the post is not covered, place a towel or other clean rag over the positive post. This will help you to avoid accidentally creating sparks by coming into contact with the positive terminal.
Loosen the nut that holds the terminal onto the negative post using a socket wrench. The nut will be located to the left of the terminal.[2]
Lift the terminal off the negative battery post. If needed, pry the terminal open with a screwdriver, or gently wiggle the connector until it loosens.
Remove the cover from the positive post.[3] Loosen the nut that holds the terminal onto the positive post by using a socket wrench. Although the negative terminal has been removed, still be careful to ensure the wrench used does not contact any other metal.
Lift the terminal off the positive post. If needed, pry the terminal open with a screwdriver or wiggle the connector to loosen the terminal.
Sprinkle the terminals with baking soda.[4]
Scrub the terminals and the posts using a special battery terminal brush, inexpensive and available at most auto parts store. This special brush has two parts, one to fit over the battery posts and another to fit inside the cable terminals. A battery terminal brush is specially designed for this job and will eliminate the need to use your fingers for cleaning. In a pinch, any wire or bristled brush will do, but, a small one will work best inside the terminals. If your brush will not fit into the interior of the terminals, try an old toothbrush or, as a last resort, use a rag draped over your finger to scrub inside each terminal.
Rinse the terminals and posts with clean water.[5]
Dry the terminals and posts with a clean towel or rag.
Rub petroleum jelly onto the posts. The petroleum jelly will help to prevent future corrosion from building up.[6]
Place the positive terminal back onto the positive post.[7]
Hand-tighten the nut until you can no longer turn it.
Place a socket wrench over the nut and tighten the nut until it no longer turns. Although the negative terminal is not connected, still be careful to ensure the wrench used does not contact any other metal.
Place the cover over the positive post. If the cover is missing, then you should cover the post with a clean towel or a rag.
Place the negative terminal back onto the negative post. Hand-tighten the nut until you can no longer turn it.
Place a socket wrench over the nut and turn it until the nut is completely tightened.
Remove all tools, towels or rags from the engine area.
Lower the support bar and close the hood.
Discard any rags or towels that came into contact with battery acid.
Community Q&A
- QuestionIs there always a clamp holding the old battery in place?
Community AnswerNot necessarily. There is usually some mechanism keeping the battery fastened, but this comes in many different forms. - QuestionHow do I remove a battery terminal cover that is stuck on? I have tried a screwdriver, WD-40, a rag with hot water, and a hammer.
Community AnswerYou could just get a pair of pliers and carefully cut it off. Just make sure not to cut the battery cable off too! - QuestionWhat should I do if I cannot remove the positive terminal because the nut will not budge, even after repeated applications of WD40?Community AnswerUse a lever on the wrench if you have enough space. Put the wrench on the nut. Put a steel pipe over the wrench; the longer the pipe, the more force will be produced. Grab the end of the pipe and push it to loosen the nut. If that won't work, then it's time to bring out the angle grinder.
Tips
- Whenever you check the fluid levels in your car, take the time to check your battery. If you see corrosive buildup, then remove the terminals and clean them thoroughly.Thanks
- To clean the battery terminals when you don’t have time to remove them, pour a can of soda over them. The acid in the soda will eat the corrosion away. Make sure to rinse the battery with clean water afterward, to prevent stickiness.Thanks
- Wash your tools thoroughly with water and baking soda to make sure that they are not damaged by contact with battery acid. Wear gloves while you're cleaning your tools.Thanks
Warnings
- Always disconnect the negative cable or terminal first when you are working with a car battery. Failure to do so could result in electrical sparks and severe burns.Thanks
- Metal may conduct electricity and cause severe burns.Thanks
References
- ↑ https://www.dummies.com/home-garden/car-repair/how-to-raise-your-vehicles-hood/
- ↑ https://shop.advanceautoparts.com/r/advice/car-maintenance/what-to-know-before-you-disconnect-your-cars-battery
- ↑ https://shop.advanceautoparts.com/r/advice/car-maintenance/what-to-know-before-you-disconnect-your-cars-battery
- ↑ https://www.dummies.com/home-garden/car-repair/how-to-check-your-car-battery/
- ↑ https://shop.advanceautoparts.com/r/car-projects/how-to-clean-battery-terminals
- ↑ https://www.meineke.com/blog/how-to-clean-a-car-battery/
- ↑ https://shop.advanceautoparts.com/r/advice/car-maintenance/how-to-connect-a-car-battery
About This Article
Removing the terminals on your car's battery may be necessary if you need to change your battery or clean the terminals. To remove car battery terminals, start by opening the hood and finding the battery in the engine compartment. Make sure the positive post has a cover, or place a towel over it to avoid creating a spark. Loosen the nut that holds the terminal onto the negative post and lift the terminal off. You can now remove the cover from the positive and negative posts. To learn how to clean the battery terminals, keep reading!
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"I learned that it is the negative terminal that should be removed first."
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