Every automotive technician job entails something slightly different, but there are some things all mechanics must know how to do. One of these services is installing lug nuts by using the right amount of torque (measured in foot-pounds). To do this, you’ll need a torque stick, impact wrench and torque wrench, and an understanding of what this important process involves.
The importance of using just the right amount of torque
Lug nuts hold the wheels of a vehicle to its axle and are thus extremely important for keeping a driver safe. Amateur mechanics sometimes make the mistake of thinking it’s best to apply as much torque as possible when installing them. The reasoning is that making lug nuts this tight should also guarantee the wheel stays in place. In reality, applying too much torque to a bolt will actually physically stretch it. By doing so, the bolt is now prone to crack, shear, loosen or even completely break off, so it’s the furthest thing from being safe. On the other end of the spectrum, a lug nut that isn’t given enough torque will not be able to stay in place once the vehicle begins moving as the force involved will quickly push it off the bolt.
Torque specifications are different for each vehicle
Every vehicle needs a different amount of torque during the installation of its wheels. The specifications should be listed in the vehicle’s owner’s manual. Industry reference guides have them too or you can simply look them up by going through ProDemand.
Installing lug nuts
Once you understand how much torque to use, you can install a lug nut. To do this, you’ll need the following tools:
- Torque stick
- Impact wrench
- Torque wrench
First, you’ll need the lug nut that the user manual requires for this specific vehicle.
Then, you’ll need a torque stick that fits it. Put the lug nut into place around the bolt and position the torque stick over its head.
Next, on the other end of the torque stick, use the impact wrench to turn the lug nut into position.
Finally, set your torque wrench to the amount specified in the manual and check your work to make sure the installation was successful.
Installing lug nuts in the right sequence
It’s essential that you know how to follow the correct sequence during installation. Installing in a clockwise manner is another mistake amateurs often make. It’s not the way any auto mechanic schools would teach.
Instead, you’ll actually follow a crisscross sequence. If you have a wheel with five bolts, imagine each has a number starting with one at the top and ending with five directly to its left. In that case, you would tighten in this sequence:
If you have six bolts with “one” positioned at the top right and “six” positioned at the top left, the sequence would look like this:
Installing lug nuts this way is the only safe method. Taking a clockwise approach will make the wheel sit unevenly on the axle which is dangerous and could result in a serious accident.
As you can see, installing lug nuts isn’t an overly technical procedure. All it takes is the right tools and following one of the above sequences, but it must be done correctly or your customers’ lives will be in danger.
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This article originally appeared on YourMechanic.com as Master Wheel Lug Nut Torque Specifications.
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