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How to Remove Corroded Car Battery Bolts

by Tim Petruccio

Automotive batteries can become corroded over time, causing them to malfunction. Corrosion or rust can form between battery posts and cable ends, causing the connection of the battery with important parts of the vehicle, such as the alternator, to be interrupted. Removing battery corrosion or rust from the terminals and cable ends will create a fresh surface for contact between the two affected contact points. You can use household items to clean your automotive batteries, though professional corrosion-removing spray and protective sprays are available at your local auto parts store.

1

Open the vehicle's hood so that you can access the battery. Inspect the battery to determine if the battery's terminals are corroded or rusted. Corrosion on the terminals will be white in color and powdery, like dried foam. Rust is brown-tinted, and will be present solely on the metal parts of the battery cables and terminals.

2

Add baking soda directly to the battery terminals, if you determine that they are corroded. Apply water to the backing soda to create a reaction between the baking soda and the battery corrosion. If the battery terminals and cable ends are rusted, spray them thoroughly with PB Blaster or a similar rust-penetrating spray. Allow the rust-penetrating spray to set for no less than 10 minutes.

3

Put on latex gloves and safety glasses while working on the battery. Scrub the battery terminals and wire ends with a wire brush or terminal cleaner tool. Remove the corrosion or rust down to the bare metal on the terminals, wire ends and wire end hardware, if possible. Pour water onto the battery to rinse away the cleaning spray used, as well as the removed rust or corrosion. Dry the top or side of the battery with a regular towel and wipe away any excess debris on the battery.

4

Loosen the tie-down nut on a top-post battery, with an open-end wrench. If the wrench spins the square headed bolt on the opposite side of the tie-down, use locking pliers or vice grips to hold down the square head. Remove the battery cables from the battery completely, beginning with the negative cable. For side-post batteries, simply remove the side posts and cables with an open-end wrench.

5

Inspect the battery terminals to ensure that the corrosion is only present on the surface of the battery. If there is more corrosion on the battery terminals, use a wire brush to thoroughly scrub them. When you are finished scrubbing, the terminals should be shiny like new metal. For side-post batteries, remove the terminals from the end of the cable wires and clean them by hand, using the wire brush. Insert the terminal ends back into the wires, and snap them in place with large pliers or channel locks.

6

Install the battery cables back onto the battery. Tighten the cables onto the battery until they are snug, using an open-end wrench. Apply anti-corrosion gel to the battery terminals on either the top- or side-post battery. Thoroughly coat the cable ends and terminals with the gel. This will help prevent future corrosion and rust from damaging the battery terminals, cable ends or cables. Remove and dispose of your latex gloves.

7

Start the vehicle to test the connections of the battery cables and ends. If the vehicle has no power, even to the dashboard warning lights, check the battery cable connections and tighten them, if needed.

Tip

  • Use a power-saving device in your vehicle's power outlet, if the outlet works when the key is in the "Off" position. The power-saving devices will keep memory functions on clocks and car stereos, and come in especially handy on stereos with lockout codes. If your vehicle outlet does not work when the key is in the "Off" position, figure out your stereo code prior to working on the battery.

Warning

  • Automotive batteries contain sulfuric acid, which is highly caustic. All batteries should be treated with extreme caution so that your skin does not come in contact with the battery acid.

Items you will need

About the Author

Tim Petruccio is a professional writer and automotive mechanic. His writing combines more than 20 years of mechanical experience in automotive service, service management, automotive education and business ownership. He assisted in the automotive beta, which launched March 2011.

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