How to Use a Torque Wrench
If you're doing necessary vehicle maintenance and repairs at home, knowing how to use a torque wrench is essential. Torque wrenches prevent the over-tightening of lug nuts on vehicles, and also ensure bolts or nuts are tight enough. Lug nuts that have been over-tightened may lead to costly repairs down the line while loose fasteners can result in a multitude of consequences. Therefore, a torque wrench helps owners prevent hundreds of thousands of dollars on unnecessary and avoidable car repairs.
Much like any tool, however, you must understand how to properly use a torque wrench. If you've never used one before, there are many valuable tips, tricks and hints you can use to make sure your car repairs go smoothly. Below, find the essential information you need to know about how to use a torque wrench.
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How Does a Torque Wrench Work?
Before you start a project, you’ll want to understand a common question among DIYers: “How does a torque wrench work?” You’ll then be better prepared to use the wrench during maintenance and repair jobs. Additionally, understanding how this tool works allows you to avoid user errors that could damage your vehicle.
Scientifically speaking, torque is defined as a twisting force. As an example, wheel lug nuts require a specific amount of applied force for safety and to maintain stability while driving. Over-tightening can subject bolts to additional strain, which can cause them to seize and stripping to occur. Ultimately, this results in damage to the wheels and axles over time. Therefore, ensuring the correct amount of torque is applied prevents this damage and improves overall stability while on the road. The same principle is true for other fasteners too.
A torque wrench measures the amount of torque applied to the bolt when you tighten it. There are three basic types of torque wrenches you may encounter, each of which works slightly differently, but ultimately achieves the same result. The three main types of torque wrenches are as follows:
- The beam type: This type of torque wrench includes a beam that has a precise amount of flexion. As you pull on the wrench, the beam bends slightly and the needle attached to it shows the value on a gauge at the base, showing the amount of torque applied to the bolt.
- The dial indicator: This torque wrench is a simplified version of the beam torque wrench. As the name suggests, this wrench includes a dial that adjusts to display the amount of torque on each bolt.
- The clicker type: The click torque wrench provides a spring-loaded mechanism that allows you to set the desired torque level. When you’ve successfully reached this level, the spring mechanics release, making a clicking sound that notifies the user that they have reached their desired torque.
Despite being different, each of these wrenches helps measure the torque, or twisting force, applied to your bolts. Among the different types are variations to choose from like a split beam torque wrench, a slip torque wrench, and electronic versions too. Ultimately, this function is the same: to determine how tight the fastener is.
Calibrating Your Torque Wrench
It’s crucial to understand how to calibrate a torque wrench since these tools are designed to take precise measurements. If it isn’t accurate, you could be under- or over-tightening fasteners. Over time, however, the measurements can become less accurate. Therefore, these tools require routine calibration to ensure they are performing correct measurements. Because of these measurements’ exact nature, it may be in your best interest to take your torque wrench to a professional to have it calibrated.
However, it’s possible to calibrate your torque wrench at home by performing basic physics calculations.
- First, you’ll want to measure the length of the handle of the torque wrench itself. Most standard torque wrenches are approximately 24 inches long; although, you should still measure yours to the nearest inch.
- Next, secure your wrench head or driver, and tighten it into the socket appropriately. You’ll then want to put a weight on the end of the wrench and calculate the appropriate setting for the weight you selected.
- Once you’ve performed your basic calculation, you’ll adjust the spring tension for your torque wrench. Typically, there’s a screw located approximately halfway up your wrench handle. By tightening this screw, you can make minor adjustments as needed to determine the appropriate torque.
The process above is only one basic guideline for adjusting and calibrating torque settings. Most torque wrenches come with a manual with directions on calibrating. It’s best to follow these guidelines as they will explain the precise calculations and step-by-step instructions for your specific wrench.
Setting and Using Your Torque Wrench
Lastly, before you perform any maintenance on your vehicle, you need to understand how to set a torque wrench. As previously mentioned, there are several different types of torque wrenches. For the gauge and beam styles, there isn’t a setting aside from watching the gauge since they’re purely mechanical in nature. However, the most common is the clicker-style torque wrench, which we will focus on here.
A traditional clicker torque wrench is relatively easy to use. To determine the amount of torque you need, you must reference your owner’s manual or other manufacturer guidelines. Torque settings are detailed here, and you must follow these instructions to avoid over-tightening bolts, nuts, and other fasteners. If you’re uncertain and no longer have access to your owner’s manual, you can often do a quick Google search to find digital copies for your reference.
Once you’ve located the torque required for each bolt, you’ll set your wrench to the correct setting on the handle. For some wrenches, slide to the right setting and begin tightening your bolts. For others, turn the handle to loosen or tighten it until you reach the correct marking. A set screw on the handle locks it in place. Then, use it. When you’ve reached the required torque, you’ll hear an audible click from the wrench.
Your owner manual will also provide you with detailed instructions on ensuring you’ve set your torque wrench to the correct torque setting. For specific questions regarding setting torque, you should reference these instructions.
Ultimately, torque wrenches are relatively easy to use and have a wide range of applications for vehicles and other modern appliances. Though it may seem overwhelming to learn how to use a torque wrench initially, eventually it becomes second nature. If you’re careful to maintain and regularly calibrate your tools, you can use your torque wrench for many years.
If you have questions or concerns about calibrating your tools or need help determining the necessary torque for your vehicle, reach out to AutoZone. Our experienced team is excited to help you tackle any project. Additionally, our extensive database allows us to easily access specific information about the make and model of your vehicle.