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Unread 12-21-2013, 10:31 PM   #1
WKDiesel
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Why do mechanics always rely on the Impact Gun

Found a cross threaded bolt after having some work done at the dealership. I'm sure it's because they used a impact gun.

Manufacturera has torque guidelines for a reason.

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Unread 12-21-2013, 11:05 PM   #2
BAH101
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Quote:
Originally Posted by WKDiesel
Found a cross threaded bolt after having some work done at the dealership. I'm sure it's because they used a impact gun. Manufacturera has torque guidelines for a reason.
But to use the torque wrench, it means you have to actually walk, over to your toolbox to retrieve it.
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Unread 12-21-2013, 11:11 PM   #3
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They are not mechanics..they are Technicians....BIG difference
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Unread 12-22-2013, 12:01 AM   #4
atarijedi
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Originally Posted by WKDiesel View Post
Found a cross threaded bolt after having some work done at the dealership. I'm sure it's because they used a impact gun.

Manufacturera has torque guidelines for a reason.
This is why I wish my warranty wasn't dependent on having someone else do all the work, or I wish I was a licensed "automotive service technician" as they are called here in Ontario, lol.
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Unread 12-22-2013, 12:08 AM   #5
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Speed.

When you're on book time, less time per job equals more money.
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Unread 12-22-2013, 12:10 AM   #6
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Just tell them to not use a impact gun take it back there and find the shop manager show him and hell probly do something about it.
I got new tires put on once the back passenger wheel almost fell off 10 miles from the place I called asked for the manager told him he sighed said take it to a mechanic to get it inspected for damage and hell pay the cost. Well I did just that they replaced a couple lugs and the part they screw on then they looked at the rest and shook their head and replaced quite a few lugs brought the shop the bill and he paid it then he went to go yell at the guy lol. Think he got his impact gun privileges taken away lol
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Unread 12-22-2013, 01:49 AM   #7
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An impact does not cross thread bolts, it just makes them easy to tighten a bolt that is cross threaded. I use mostly hand tools, impacts do have there place, most professional mechanics don't know the actual time and place.
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Unread 12-22-2013, 02:04 AM   #8
xrunndonex
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Originally Posted by terrasmak View Post
An impact does not cross thread bolts, it just makes them easy to tighten a bolt that is cross threaded. I use mostly hand tools, impacts do have there place, most professional mechanics don't know the actual time and place.
Yes it can. Also it can stretch the threads from over torquing. Impact wrenches were not designed to be used to tighten bolts. Lug nuts should be done by hand so you know they are at spec
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Unread 12-22-2013, 06:01 AM   #9
terrasmak
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Originally Posted by xrunndonex View Post
Yes it can. Also it can stretch the threads from over torquing. Impact wrenches were not designed to be used to tighten bolts. Lug nuts should be done by hand so you know they are at spec
As mentioned, it does not cross thread, it just lets you tighten a bolt really easy that is cross threaded. I do agree that hardware should not be torqued with an impact. I do it all the time anyhow, kinda, just snug and torque with hand tools.
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Unread 12-22-2013, 09:01 AM   #10
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It was mentioned already but time is money - that's why they use airtools. If they did everything by hand then you'd pay more than the ridiculous amount of money than you already do. Which is why I do about 90-95% of all maintenance/upgrades on our Jeeps myself.

The problem isn't the airtool - it's operator error. Most any impact gun has torque settings, you can get different size drives, and you always start and finish (especially critical torque specs) by hand.
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Unread 12-22-2013, 09:02 AM   #11
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One of the problems is the difference in torque depending on the vehicle. My CTS is 140lbs while the WK is about 100lbs. Hopefully the mechanics remembers to reset the impact wrench after putting tires on the CTS with a WK being next in line.
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Unread 12-22-2013, 09:17 AM   #12
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Yes, it's all user error and it depends on what shop your going to. I work at discount tire and when we mount up a wheel, start all lugs by hand to avoid crossthreading, then tighten down lugs with air gun with torque stick attached to gun that will only allow it to be tightened to 70 ft. Lb.'s, and then torque it down to manufacturer specs. Air tools are wonderful tools if used correctly.
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Unread 12-25-2013, 01:50 PM   #13
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That's just one thing to worry about. Torque wrench is only good if it has been calibrated and they know how to use it. Once it clicks you stop tightening, you don't continue tightening. Is the torque spec really a dry instead of wet or vice versa? Shear vs tension, course vs fine, it goes on and on.
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Unread 12-25-2013, 04:03 PM   #14
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Originally Posted by xrunndonex View Post
Yes it can. Also it can stretch the threads from over torquing. Impact wrenches were not designed to be used to tighten bolts. Lug nuts should be done by hand so you know they are at spec
Sorry no it can't.If the lugnut(or bolt or what ever) was started by hand with good threads on both surfaces,not gummed up and clean,a impact can not and will not cross thread the fastener.
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Unread 12-25-2013, 04:52 PM   #15
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Originally Posted by tjkj2002 View Post

Sorry no it can't.If the lugnut(or bolt or what ever) was started by hand with good threads on both surfaces,not gummed up and clean,a impact can not and will not cross thread the fastener.
That's if the mechanic / technician starts it with hand. Then it's all good. Guess it's all about the user.
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