How to Remove Car Battery Terminals

Co-authored by Duston Maynes

Last Updated: March 19, 2024 References

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.

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Method 1

Method 1 of 3:

Removing the terminals

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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.

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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.
The nut will be located to the left of the terminal.^{[2]
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If needed, pry the terminal open with a screwdriver, or gently wiggle the connector until it loosens.
^{[3]
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If needed, pry the terminal open with a screwdriver or wiggle the connector to loosen the terminal.

Method 2

Method 2 of 3:

Cleaning the terminals

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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.
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The petroleum jelly will help to prevent future corrosion from building up.^{[6]
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Method 3

Method 3 of 3:

Reconnecting the terminals

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Although the negative terminal is not connected, still be careful to ensure the wrench used does not contact any other metal.
If the cover is missing, then you should cover the post with a clean towel or a rag.
Hand-tighten the nut until you can no longer turn it.

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Question

Is there always a clamp holding the old battery in place?

Community Answer

Not necessarily. There is usually some mechanism keeping the battery fastened, but this comes in many different forms.

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Question

How 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 Answer

You could just get a pair of pliers and carefully cut it off. Just make sure not to cut the battery cable off too!

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Question

What should I do if I cannot remove the positive terminal because the nut will not budge, even after repeated applications of WD40?

Community Answer

Use 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.

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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.

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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.

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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.

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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.

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Metal may conduct electricity and cause severe burns.

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