Impact Wrench
A pneumatic or battery-powered tool designed to deliver high torque output with minimal effort to remove stubborn fasteners.
An impact wrench (also known as an impact gun) is a high-torque power tool designed to tighten or loosen fasteners quickly. It uses an internal hammer mechanism that strikes an anvil repeatedly, converting rotational energy into short, high-force impacts. This pulsating torque allows the tool to loosen rusted, seized, or over-tightened bolts that would require immense effort with a breaker bar.
Impact wrenches can be powered by compressed air (pneumatic), which is the standard in professional repair shops, or by high-voltage lithium-ion batteries, which offer portability. They are classified by drive size, with 1/2-inch and 3/8-inch drives being the most common for automotive work. They are primarily used for quick removal of lug nuts, suspension bolts, and subframe mounts.
When using an impact wrench, it is essential to use specialized impact sockets, which are made of thicker, ductile chrome-molybdenum steel to withstand the hammer blows. Standard chrome sockets can shatter under impact force. Additionally, impact wrenches should not be used to final-torque critical bolts (like lug nuts or head bolts), as they can easily over-tighten and damage threads.