An impact wrench works on the principle that its name suggests: impact. A manual wrench needs to be hammered to produce a rotating motion on the nuts, and an automatic one does that with small built-in hammers. Using an impact wrench to torque any type of nuts requires a fair amount of expertise. To torque lug nuts, most people in traditional garages use a manual torque wrench. Recently though, the use of an impact wrench to torque lug nuts has become increasingly popular, as it does the job in less time and takes less effort. Expertise, however, is very important to make sure lug nuts don't break. This step-by-step guide will help take you through learning what is required to torque lug nuts using an impact wrench. The tools and materials required for the job are given below.
Step 1 - Learn the Pattern That is Used to Torque Lug Nuts
Whether you are using a torque wrench or an impact wrench, lug nuts have to be tightened in a specific pattern. The pattern that is most commonly followed is called the 'star pattern'. It is a pattern in which the lowest left nut is tightened first, then the top nut, then moving to bottom right, left and right nut to complete a star. Following this pattern will ensure that a uniform tightening process takes place. Any other pattern can put pressure on un-tightened nuts and cause damage to the lug nuts.
Step 2 - Use Your Hand
The first step before you start actually tightening lug nuts on your car wheels is to use your hand. Using an impact wrench is a tricky process. If you start tightening the nuts with the impact wrench itself, you won't be able to feel whether the lug nut is placed correctly on the threads or not. If you just place the nut on and start tightening it with an impact wrench, you risk the threads getting crossed and damaged. Tighten the lug nuts as much as you can using your hand first.
Step 3 - Torque Lug Nuts with an Impact Wrench
Once you have tightened the lug nuts to the point that they can't be tightened anymore by a human hand, you can use the impact wrench. The impact wrench produces a hammering motion to tighten the nuts. Tighten the nuts on the wheel in a star pattern as explained in step 1. It is very important that you do this very carefully. If you don't stop the impact wrench in time, a over-torquing can break the nut. The best way to go about this is to provide torque to the lug nuts in short bursts, remove the impact wrench, and check with a torque wrench to see if the nuts need more tightening. This can somewhat slow down your process, but it will still be quicker than doing the whole thing with a torque wrench alone.