Impact Gun

Published: June 6, 2017

An impact gun makes many jobs quicker, and some a lot less frustrating.

I like having two impact guns - a big one and a small one. My big gun currently is a Dewalt 20v max 400 ft-lbs unit. This gun will take axle nuts off torqued to 200 ft-lbs on a full battery charge. I did find fasteners it would not budge - those were control arm long bolts rusted to the uprights, and in some places the gun itself does not fit with the sockets I had (over a Miata crank pulley for example).

Jobs for the big impact gun are: - Removing lug nuts - Removing axle nuts - Removing nuts and bolts on parts already removed from the vehicle where leverage would be difficult to achieve with a breaker bar - Removing subframe and suspension fasteners

The Dewalt gun comes with a small battery. This makes the gun easier to handle as well as fit in places, however the battery seems to cycle out very quickly, especially in cold weather, to the point where the battery life becomes almost nonexistent. I just about go through a full battery charge taking the wheels on and off the car at a track day, in one day. My gun is less than a year old and in winter the batteries are almost useless even when they are fully charged.

The small gun I have is currently a Makita 18v Lithium unit, although just about any gun should work. The purpose of the small gun is to operate small fasteners without risking twisting the head off due to excessive torque being applied. Ideally both guns would use the same batteries - mine don't for historical reasons.

Jobs for the small impact gun are: - Interior fasteners - Body panel fasteners - Getting out already loosened bolts quickly

A nice thing about the Makita gun is its batteries last a long time. It is also quite compact and a good bit smaller than the big Dewalt gun (although Dewalt makes smaller impact guns with lower torque ratings).