DIY – Fixing a broken battery retainer with a battery strap

4

September 20, 2013 by quirkyuncle

The acid in car batteries is highly corrosive. It can create an environment near the battery that damages parts of your car. Here is an easy and inexpensive fix that you might be able to use, if the hardware that secures your battery corrodes and fails.

Battery warning

When replacing the battery in our car, we discovered that the battery hold-down bolt had rusted and seized in place; the bolt broke when we tried to remove it. Due to the structure of the battery tray, I could not drill another hole to install a new bolt, since the hold-down clamp is designed so it cannot slide from position.

A new battery tray for this car cost about $30. While this is not a prohibitive amount, I thought there might be a less expensive alternative that would work just as well. I ended up buying an acid-resistant nylon battery strap, designed for use in boats, for $7. It holds the battery far more securely than the original clamp, making it a safe and effective solution.

Battery strap

Note: While this task is shown being performed on a 2000 Ford Mustang, the techniques it uses can be applied to a wide range of vehicle types.

The procedure in this posting is divided into the following sections that can be used independently:

Tools and Time

Tools: Essential tools
Time: 30 minutes
Difficulty: Easy

You can order a battery strap from Amazon.com.

Problem Assessment

Each car is unique and you’ll need to evaluate which solutions might work for your specific vehicle configuration. Pay attention to how the battery mounted to determine:

  • Can a new bolt be installed?
  • Is there room underneath the battery tray for a strap?
  • Is the tray itself rotted? If so, it should be replaced.

There are many valid ways to fix most problems. Whatever method you come up with must be as secure as the original mounting method, so that no additional damage or injury will be incurred, if the car is ever in an accident.

Remove the Battery

Note: I plan to be cover battery removal in greater detail, with photos, in an upcoming posting. For now, the following steps should be sufficient.

Warning: Always handle a battery with extreme caution.

  • Batteries are filled with strong acid. DO NOT GET ANY BATTERY ACID ON YOU, YOUR CLOTHING, OR YOUR CAR! Immediately rinse any battery spills with lots of water. If you get acid in your eyes, flush them with water right away and seek immediate medical attention!
  • Batteries are very heavy. Batteries can weigh 50-pounds or more and can be installed in locations that require you to lean over when removing or installing them. USE CARE WHEN LIFTING!
  • Batteries can emit explosive hydrogen gas. This gas can be ignited by sparks or open flames. Be careful!
  • Batteries store a lot of electrical power. Do not bridge across (allow connection between) the positive and negative battery terminals with anything metallic or electrically conductive. Always disconnect the negative battery cable first and connect the negative battery cable last.

If the battery case is damaged or leaking, replace the battery.

To remove a car battery, complete the following steps:

  1. Using a wrench, loosen the negative (- or black) battery connector clamp. You do not need to fully remove the bolt or nut from the clamp. Use care not to drop or lose any hardware. Make sure you do not bridge across the positive and negative battery terminals with the wrench.
  2. Lift the negative battery connector clamp from the battery post. Do not pry against the battery casing. Spread the clamp with a screwdriver, if necessary, to work it loose. Bend the negative battery cable away from the negative battery terminal so that it does not touch the terminal.
  3. Using a wrench, loosen the positive (+ or red) battery connector clamp. You do not need to fully remove the bolt or nut from the clamp. Use care not to drop or lose any hardware. Make sure you do not bridge across the positive and negative battery terminals with the wrench.
  4. Lift the positive battery connector clamp from the battery post. Do not pry against the battery casing. Spread the clamp with a screwdriver, if necessary, to work it loose. Bend the positive battery cable away form the positive battery terminal so that it does not touch the terminal.
  5. Remove any hardware that is securing the battery in the battery tray.
  6. Remove the battery vent tube, if one is installed.
  7. Note how the positive and negative battery terminals are oriented. You must install the battery so that the positive and negative terminals connect the same way. Installing a battery backwards will damage your car.
  8. Carefully lift the battery from the car and place it on the ground.
  9. Clean the battery tray.
    • Remove loose debris.
    • Clean acid scale using battery cleaner spray, a solution of baking soda and water, or Coca-Cola. Rinse thoroughly, if possible, or wipe the area clean using something disposable, such as a paper towel. Use care and restraint when cleaning a battery tray that is mounted in the trunk or in a car’s interior.

Install the Battery Strap

To install the battery strap, complete the following steps:

  1. If necessary, loosen the battery tray, so that the strap can be threaded beneath it. For the Ford Mustang, I removed the two screws securing the battery tray to the inner fender.
  2. Work the battery strap under the battery tray. Use care to avoid placing the strap anywhere where it can be damaged by screws or other sharp edges or objects.

    thread strap under battery box

  3. Position the battery strap so the clasp will be in a good location after the battery is installed. The clasp needs to be accessible so you can tighten and loosen the battery strap and should not be in a location where the clasp can interfere with any other automotive components or covers.
  4. Secure the battery tray, installing any hardware that was removed to loosen it.

Install the Battery

Note: I plan to be cover battery installation in greater detail, with photos, in an upcoming posting. For now, the following steps should be sufficient.

To install a car battery, complete the following steps:

  1. Check the battery fluid levels (If you don’t know how, wait until I provide instructions in another posting.)
  2. Clean the battery. Clean acid scale from the battery casing using battery cleaner spray, a solution of baking soda and water, or Coca-Cola. Rinse thoroughly. (Do not get any acid neutralizing chemicals that you are using to clean the battery inside the battery: these will reduce your battery life.) Dry the outside of the battery case: allow it to air dry or use something disposable to dry it such as a paper towel.
  3. Carefully lift the battery into the car and place it in the battery tray. Make sure that the positive and negative battery terminals are oriented in the same way that they were prior to battery removal.
  4. Connect the battery vent tube, if one was removed.
  5. Install any items that were used to secure the battery which were removed. The original battery clamp, with missing bolt, is shown below. I ended up retaining the original battery clamp with a zip-tie to help prevent the battery from sliding around in the battery tray.
    battery clamp in place or broken
  6. (Optional) Apply battery terminal grease to the battery posts and connector clamps to prevent corrosion. This grease is available in small packets at most auto parts stores. It is very inexpensive and really does help prevent the battery connections from corroding.
  7. Place the positive (+ or red) battery connector clamp on the positive battery terminal post. Press the clamp down fully and tighten it with a wrench. Make sure you do not bridge across the positive and negative battery terminals with the wrench. Battery connector clamps are typically made of a soft metal: do not over tighten them or you will stretch the clamp. The clamp is tight enough when you can’t twist it from side to side on the battery terminal post using your fingers.
  8. Place the negative (- or black) battery connector clamp on the negative battery terminal post. Press the clamp down fully and tighten it with a wrench. Make sure you do not bridge across the positive and negative battery terminals with the wrench. Battery connector clamps are typically made of a soft metal: do not over tighten them or you will stretch the clamp. The clamp is tight enough when you can’t twist it from side to side on the battery terminal post using your fingers.

Secure the Battery

To secure the car battery, complete the following steps:

  1. Loop the battery strap over the top of the battery and insert the strap through the clasp.
    thread strap over battery
  2. Slide the battery strap so the clasp is well positioned. The strap should not be in contact with any sharp objects and should not be pressing on the battery cables or vent caps, as shown in the the following photo.
  3. Pull the battery strap tight.
    tighten strap
  4. Dress any excess batter strap and secure it so that the strap does not unravel and interfere with any nearby automotive components. (If a loose strap got pulled into the engine fan or drive belts, that would be bad.)
    dress strap
    If you decide to cut off any excess length from the battery strap, make sure that you do not make the strap too short to grab during a later battery replacement. The ends of a cut nylon web strap should be fused with a match or cigarette lighter, or covered in tape, to prevent the strap from unraveling (Remember, no open flames near the battery!)

4 comments »

  1. How did the strap hold up over time under the engine bay?? Any issues from excess heat melting plastic parts? Just curious as I will be doing this tomorrow.

    • quirkyuncle@gmail.com says:

      Hi, Dinesh.

      The strap held up well until we sold the car 1-1/2 years after we installed it. I’d suspect it would remain functional for several years.

      The under hood environment is very hard on plastics, with it’s high temperature extremes and harsh chemicals. Keep an eye on the strap as it ages and replace it if it starts to fray or become brittle. The battery case is made of plastic, so it should not be mounted near extreme heat sources, such as the exhaust manifold, in the first place.

      Good luck with your install. Let me know how it turns out.

  2. Belle says:

    would it be ok to use a strap made of metal instead of nylon/plastic?

    • quirkyuncle@gmail.com says:

      I would not use a metal strap as it would be prone to corrosion and if it shifted could short the battery terminals or short the positive battery terminal to the chassis.

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