Here's another example:





Trying to salvage the brake junction from a parts car. The brake line ports looked good, but the shuttle was frozen in place by rust. Even the nylon switch was seized beyond reasonable release with a hand twist. Figured the impact wrench couldn't make it any worse. Snap.

Lesson was not so much about impact vs. brute force, but that these warning devices can fail "without warning" when the shuttle gets frozen in the middle.
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Art Benstein near Baltimore

"If a woman has to choose between catching a fly ball and saving an infant's life, she will choose to save the infant's life without even considering if there is a man on base." (Dave Barry)

Is your impact wrench adjustable, and if you use it at a lower setting, I think that taking things apart has little risk. At a low setting, below the tightening torque, the impacts may loosen a fitting better than constant force.

The question is how to set the torque that it generates.

You could experiment with trying different settings to tighten lugs and checking the torque with a torque wrench. Or torquing the lugs to a particular value and seeing what setting loosens them.

I would be more fearful of cross threading.

The time saved in changing a set of wheels might be worthwhile, but how much time could you save taking your front end apart? How many fasteners are involved?

Sometimes, when you break a bolt, you can see that it already was damaged before you broke it.

A few days ago I had to replace the spark plugs in my V70 (Alum head). They had been in there for several years and 85,000 miles. Most of them backed out fairly effortlessly, however one in particular did not want to unscrew without a battle. I unscrewed it about a half turn at which point it became VERY TIGHT and I started to worry. I screwed it back in a bit, then unscrewed to where it got tight again, screwed it back in, then back out, etc. Each time I unscrewed it I went a little bit further until it had lifted enough to spray some lubricant down under the washer, hoping it would soak down into the threads. Screw in - screw out - screw in - screw out. Man, was my arm getting tired! I used a medium length ratchet so as to not apply too much torque. Eventually I got it out with no thread damage and without snapping the spark plug in half.

About half way through the process I started thinking what would have happened if I had taken it to the wrong repair shop and some knuckle head tried backing it out with an impact gun?
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)