Impact Wrench for Wheels Nut/ Lug Nuts

My brother bought a big hitachi cordless set the other week, it includes that impact wrench. I love the thing. I would never have been able to undo some nuts without it.
When putting on my wheel nuts, I get them started by hand until they are a couple of threads on and then give them a quick spin with the wrench, but I don't allow them to go tighter than the 110Nm setting on my torque wrench.

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Originally Posted by string

With dirty threads you're almost guaranteed to under torque it. Even with perfectly smooth lubricated threads, it's an artform to accurately use a torque wrench.

All I know is that I tighten the lugs up "pretty ****in' tight" by hand and I've had a total of zero problems in the 5 years I've been working on cars.

As a relevent reference, ARP head studs (the ones I bought anyway) are rated at 75ft-lb using moly disulphide grease, and 85ft-lb with 10w-30 motor oil. What do you think the torque requirement would be for rusty threads?

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surface rust can be cleaned and should be if present :) then there's the same values in place

Quote:

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Originally Posted by string

With dirty threads you're almost guaranteed to under torque it. Even with perfectly smooth lubricated threads, it's an artform to accurately use a torque wrench.

All I know is that I tighten the lugs up "pretty ****in' tight" by hand and I've had a total of zero problems in the 5 years I've been working on cars.

As a relevent reference, ARP head studs (the ones I bought anyway) are rated at 75ft-lb using moly disulphide grease, and 85ft-lb with 10w-30 motor oil. What do you think the torque requirement would be for rusty threads?

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fair enough - i'm not having a go at you mate :) i've always used a torque wrench on my lug nuts and guess what? i've also had a total of zero problems in the 3 years i've been working on cars.

doesn't mean i'm doing it right :)

i don't know what the torque requirement is for rusty threads and i gather neither do you. perhaps you will undertorque it but can you give a figure as to how much you will undertorque it by? is it 5% (doesn't matter), 20% (probably doesn't matter) or 80% (yeah wheel is coming off)?

do you suppose 'pretty ****ing tight' is more accurate than a torque wrench? how do you know your rusted threads aren't causing so much friction that your PFT measurement is under the factory spec?

again don't think i'm having a go at you because you seem to be quite knowledgeable. just saying this because i like torque wrenches and i believe many of the evils in the car world can be cured by their use :)

I use a torque wrench as over tightening can lead to a repair cost greater than the current task at hand lol

By all means use a torque wrench, just don't convince yourself it's perfect because the wrench clicked.

IMO there's too many factors before you even consider calibration and accuracy, which is why I do 99% of bolts up by hand. I'd much prefer to do them up hard enough that [from experience] I know they won't come undone, than to be lulled into a false sense of security through a gauge reading. If you're willing to fully prepare the threads then more power to you, but I'm a backyard mechanic who trusts his instincts and prefers to save time which could be better spent drinking beer and playing computer games.

Quote:

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Originally Posted by string

By all means use a torque wrench, just don't convince yourself it's perfect because the wrench clicked.

IMO there's too many factors before you even consider calibration and accuracy, which is why I do 99% of bolts up by hand. I'd much prefer to do them up hard enough that [from experience] I know they won't come undone, than to be lulled into a false sense of security through a gauge reading. If you're willing to fully prepare the threads then more power to you, but I'm a backyard mechanic who trusts his instincts and prefers to save time which could be better spent drinking beer and playing computer games.

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amen to that :thumbsup:

Hi Guys,

All well said. All the information given on this thread == GOLD!!! Reps given!

Cheers

hey Cymax, Its Max here.
My mate that you met at Wakie has this small impact that you plug into the ciggarette socket in the car. Its not very powerful at all but I loosen the nuts with the wrench and then use the gun to take it off.

To put them on, I use the gun and then hand tighten with wrench. You only need to nip it up a little bit to tighten it.

I can find out where he got it from and what brand if you want.

just some hints guys -

1. do not TIGHTEN lug nuts when WARM or HOT ( Ie directly after car use) IT can snap lug nuts or round lug nuts/lugs.

2. An impact gun (electric) will never apply the correct torque when tigthening. Use a proper decent torque wrench to get CLOSE to the correct torque , tigthen in a cross pattern and also tighten slightly over spec IMO. ( 108NM + )


For the best combo....you need a 1/2 inch 2 + foot long breaker bar , DEEP 6 sided impact sockets , a proper torque wrench that reads atleast to 200nm or so. As for the IMPACT gun ....unless you are a DIY guy like me dont bother. You cant rely on the impact gun to do everything ( untighten and tigten to spec) .
I personally use a ratchet or breaker bar to CRACK/LOOSEN any lug nuts or others first , then go over with the impact gun to take off. When putting back on use the impact gun to lightly tigthen ( IE quick BLAP BLAP BLAP) then finish off with a torque wrench set to the relevant torque.

yes torque wrench is the best thing for tightening lug nuts.

you should not need a breaker bar to undo your lug nuts that is way to tight. Check the service manual for the correct torque ammount, you should find it wont be very much!

Quote:

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Originally Posted by rossirider

hey Cymax, Its Max here.
My mate that you met at Wakie has this small impact that you plug into the ciggarette socket in the car. Its not very powerful at all but I loosen the nuts with the wrench and then use the gun to take it off.

To put them on, I use the gun and then hand tighten with wrench. You only need to nip it up a little bit to tighten it.

I can find out where he got it from and what brand if you want.

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Hey Mate! How is it going! Yeah, what's the brand? Think it'll be helpful and it'll be more cost efficient doing your way. Share with ppl here. Think they'll be interested to know. :)

Think I'll invest one torque wrench as well.... where do you guys reckon I can get one a cheap one? SCA?