I broke two of my car's lug nut studs, and I had to take the car to mechanic for repair. The mechanic explained that sometimes lug nuts are highly over-torqued because all shops use impact gun to tighten them, but does not cause any problems as long as they are opened using an impact wrench.
Also, my mechanic explained that using a breaker bar (like below) in over-torqued situations can damage the studs.
Is to correct to say that avoiding breaker bars and using an impact wrench instead prevents damage to nuts or bolts?
Is it correct to say that over-torquing lug nuts with an impact gun is fine as long as we open them with impact gun rather than a breaker bar?
I understand and completely agree that a torque wrench is the best approach. However, that is not the context of this question. So we should move from the ideal world to real world where most mechanic shops use impact gun. When we need to open to open an over-torqued lug nut, I can think of 3 options to handle the situation:
- Option 1: use a breaker bar. Well that broke my lug stud :(
- Option 2: Use an impact gun to open the lug nut. My mechanic claims that it always works for him without breaking the stud. He suggested that I should have used this option.
- Option 3: use a lubricant such as W40. Many people don’t like the idea since it changes the torque spec of the lug nuts
The question is which of the above option should I consider or is there a better option?
I 100% agree that a torque wrench should be used in the 1st place. However, when we end up with an over tighten nut, a breaker bar can cause more damage compare to a similar rotational force created by a four-way or torque gun. It was a mystery to me how come my mechanic never ended up breaking my lug studs, and I broke 4 of them at the 1st try!! He always uses a torque gun, and I used a breaker bar.
Once again, I 100% agree that a torque wrench should have been used in the 1st place. Can't emphasise it enough
It costed me $160 to earn this experience, I hope this post save someone else's lug studs :) It is possible to find a fine corded impact wrench for $40, which is fine for home use. I got this one: http://www.homedepot.ca/product/18-volt-one-1-2-in-cordless-3-speed-impact-wrench-tool-only/919361 here is a demo video: https://www.youtube.com/watch?v=CvvDYHZ-GeM