How to Replace a Battery Cable Clamp

by Francis Walsh

Battery connections should be clean and free of debris, with tightened clamps at the end of the cables to secure them to the power posts of a 12 or 16 volt auto battery. The charge in the battery flows throughout the electrical system for starting the car and for any of its electrical needs; it gets recharged while you drive the car. At times this electric charge can be prevented from doing its job because of an oxidized cable clamp that has lost a good connection with the battery. If the clamp is so damaged that it cannot be tightened securely around the battery post to make a good connection, you will need to replace the clamp in order to complete the electrical circuit of a vehicle.

Park the vehicle on a flat surface. Clean around battery connections that are heavily oxidized and corroded with battery debris. The crusty buildup can be properly cleaned once the cables have been disconnected. Use a wrench to loosen the nut or bolt that tightens the clamp onto the battery post. Wiggle the clamps away from the posts.

Clean the battery cable clamps and cable ends until they are free from dirt and debris. Use the wrench to loosen the nut that secures the battery clamp to the cable. Remove the bad cable clamp and examine the end of the cable. Remove the cable end if it is pitted and scarred by corrosion. Use a utility knife to cut back the protective wire cover to expose clean, fresh cable. Snip the bad end off.

Slide the new battery cable clamp over the end of the cable that has the newly exposed wire end. Tighten the fasteners of the clamp so that the clamp sits evenly on the wire. There should be no exposed wire in-between the base of the clamp and the wire's protective covering. The cable should have only enough wire exposed to fit inside the camp and be secured tightly.

Clean the battery posts completely with a wire brush. The battery posts should have no leftover debris. You can use sandpaper on the posts as long as they are brushed clean of dust and dirt afterward. Make sure the battery is secure in its location.

Slide the new battery cable clamp over the battery post and use a wrench to tighten the clamp onto the post. Repeat the process for both positive and negative poles. Test the connection by turning on the vehicle's dome light, then starting the car up. Notice any hesitations or problems with the start. Check the voltage gauge and confirm that the battery is charging and discharging correctly. If so, the job was successful. If not, check the connections at the other ends of the cable to look for a problem there as well.

Tip

  • check Sometimes even after the cable fix the battery will be so low the car will not start. Charge a worn battery to test the new battery clamp correctly.

Warning

  • close Do no get a screwdriver or any other object in between the positive and the negative posts of a car battery. This creates a dangerous discharge of electric current that can injure people with an electrical short circuit shock. This type of mistake has even been responsible for explosions of batteries that are weak and poorly maintained.

Items you will need

About the Author

Francis Walsh has been working as a freelance writer since 2003. He has contributed to websites such as Shave, Autogeek and Torque & Chromeas, as well as provided content for private clients. Walsh has worked as a performance part-packer and classic car show promoter, now serving as crew chief for Nitrousfitz Racing.