How to Remove Car Battery Terminals

Last Updated: September 2, 2020 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.

Method 1

Method 1 of 3:

Removing the terminals

1
Open the hood of the car and use the support bar to prop it open.^{[1]
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2
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.

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3
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.
4
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]
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5
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.
6
Remove the cover from the positive post.^{[3]
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Research source} 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.
7
Lift the terminal off the positive post. 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

1
Sprinkle the terminals with baking soda.^{[4]
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2
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.
3
Rinse the terminals and posts with clean water.^{[5]
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4
Dry the terminals and posts with a clean towel or rag.
5
Rub petroleum jelly onto the posts. 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

1
Place the positive terminal back onto the positive post.^{[7]
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2
Hand-tighten the nut until you can no longer turn it.
3
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.
4
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.
5
Place the negative terminal back onto the negative post. Hand-tighten the nut until you can no longer turn it.
6
Place a socket wrench over the nut and turn it until the nut is completely tightened.
7
Remove all tools, towels or rags from the engine area.
8
Lower the support bar and close the hood.
9
Discard any rags or towels that came into contact with battery acid.

Community Q&A

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.
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!
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.

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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