View Full Version : Cordless Impact Driver for a Car

Mike Henderson
07-13-2015, 12:47 PM
A while back, there was a thread about how difficult it is to remove lug nuts on wheels when the auto shop uses an impact tool to put them on. I had a situation a while back where I had a flat and couldn't get the lug nuts off - had to wait for AAA to show up with a cordless impact tool.

I thought about putting a cordless impact tool in my car but I know that the battery would be dead when I need it. But then, I thought about an impact tool that could be hooked to the car battery, perhaps through the cigarette lighter. If not that, then maybe with clips on the battery.

Do you know of anyone who makes an impact tool like that, or a converter that will hook to a car battery and power a regular cordless impact driver? Something that would replace the battery on the tool, not something that will charge a tool battery. It would take too long to charge a dead cordless battery.

Does DeWalt, Makita, Ridgid, or any of the name brand tool makers have such an adapter?


[Mods, if this should be in Off Topic, please move.]

Matt Meiser
07-13-2015, 1:40 PM
If nothing else you could easily make something from a bad battery pack. I have seen cigarette lighter powered impact guns but nothing name brand.

Craig Hoehn
07-13-2015, 1:46 PM
For the amount that youre going to use it, why not keep a larger breaker bar in the trunk for loosening the lug nuts?

Bruce Page
07-13-2015, 2:14 PM
For the amount that youre going to use it, why not keep a larger breaker bar in the trunk for loosening the lug nuts?

I agree. A 24" breaker bar with a good 6 point socket should break any car lug nut loose, or break the stud trying. They're not very expensive.

Dan Rude
07-13-2015, 2:49 PM
I have no idea on the brand but there is a 12v on Minneapolis Craig's list. Or just get an inverter and a corded one like an hf. Make sure the inverter has the wattage though. Dan

mreza Salav
07-13-2015, 3:00 PM
Better yet, keep a (long) torque wrench that can be used as a breaker bar and tightening the nuts to a correct (specified) torque.

Jim German
07-13-2015, 3:20 PM
First, you'd want an impact wrench instead of an impact driver. Most Impact Drivers put out less than 2,000 in-lbs of torque which frequently won't be enough to break lose a lug nut. Milwaukee makes a 18V impact wrench that puts out 1,100 ft-lbs of torque though. Lots of ways to keep it chargered, Milwaukee makes a car charger for the M18 batteries.

There are a few 12V impact wrenches on the market, specificlly for keeping in the car in an emergancy. Here's one. (http://www.amazon.com/Wagan-2257-12V-Impact-Wrench/dp/B0038KNJQ6/ref=sr_1_2?ie=UTF8&qid=1436815017&sr=8-2&keywords=12V+impact+wrench) Most of em seem pretty cheap though, I don't know that I would trust them in an emergancy. Like others have mentioned I just keep a big breaker bar in the car isntead. $20 from sears and don't have to worry about the power. If you're really concerned you could throw a cheater pipe in too.

Mike Henderson
07-13-2015, 3:28 PM
Yep, I thought of a breaker bar. I have a piece of 1" pipe that slips on the end of a "socket bar" that I use for breaking loose tight nuts. I just thought I'd see if anyone knew of an impact wrench that would hook to a car battery.

@Jim, yes, I know the difference between an impact wrench and an impact driver. I just used the wrong terminology. Sorry.

Thanks, everyone, for your comments and suggestions.


Jim Dwight
07-13-2015, 4:25 PM
A quick google search turned up several 12V impact wrenches. I only scanned them but didn't see torque specified. I have a 18V Harbor Freight impact wrench my son gave me when we were replacing floats on the dock. It is rated for 330 ft lbs but a review I saw said it's real torque is closer to 200 ft lbs. But that is plenty for lug nuts. Unless they've been tightened with an air impact stronger than that. You can get 1/2 inch air impacts rated over 700 ft. lbs. No lug nut should ever be that tight but.... I know mine have been tight enough I could get them with a star wrench or my 18V or my 1/2 torque wrench. So I took the car back to the place that put the wheels on and had them loosen them and retighten with a torque wrench. They didn't argue and didn't charge me.

Long way of saying nothing you can put in your trunk, short of a compressor and 700 ft. lb. torque wrench will take your nuts off for sure. Best to check them after tire changes and make the garage fix them if they're too tight.

I carry an extendable 3/8 ratchet in my tool roll in the trunk of my convertible and a 3/8 break over bar and a piece of pipe in the SUV. Those are enough if the lug nuts are properly tightened. If the lug nuts are overly tight, even a cordless or 12V impact wrench may not be enough either.

Matt Meiser
07-13-2015, 6:41 PM
The 18v name brand impacts have a really good reputation.

Jim Dwight
07-13-2015, 8:38 PM
My son, same one that gave me a HF, loves his Milwaukees. For how much I use it, the HF was a better idea. For the money, it is a very nice tool.

Earl Rumans
07-13-2015, 8:55 PM
i don't know of any 12v impact wrench that will reliably remove lug nits that were put on with an air impact. You would need to go with an 18v wrench and you are talking about a lot of money for something that you may never use. Just get a good 4 way wrench and a short piece of pipe and keep them in you spare tire well, problem solved.

Martin Wasner
07-13-2015, 9:17 PM
I've got a " drive, 24" breaker bar and a 4" extension with a couple of sockets (7/8" for the pickup, 13/16" for the trailer), in the door of my pickup. It's only been used a few times in the 250,000 miles it's been rattling around, but it's been a lifesaver.

peter gagliardi
07-14-2015, 10:16 AM
Better yet, keep a (long) torque wrench that can be used as a breaker bar and tightening the nuts to a correct (specified) torque.
All well and good, except torque wrenches are not designed for removing lug nuts/ breaker bar applications, and you can ruin their accuracy doing so. FWIW.

David Hawxhurst
07-14-2015, 10:32 AM
i have the IR impart wrench and it out performs most air impact wrench. i normally don't carry this in the car, but i do have a 24" breaker bar and the deep well six point socket in each of our vehicles.

johnny means
07-14-2015, 10:01 PM
You could correctly torque your lug nuts in your driveway. Then all you would need is the jack and wrench they came with the car. I wouldn't want to be dependent on any electrical gadget in a pinch.

John Lankers
07-14-2015, 11:14 PM
I used to change 60 shanks on my air drill in the field with an 800 watt inverter and an old DeWalt 110 Volt impact wrench (engine running of course).

Jim Dwight
07-15-2015, 9:20 AM
When I couldn't get my lug nuts loose with my 18V impact that is limited to about 200 ft. lbs I took it back partically because I was worried about breaking them. I could have put a long pipe on my breaker bar but that would have risked snapping the bolts. Lots of leverage isn't always the right way to go.

I agree with the checking them post. I try to rotate my tires when I change oil (every 5K miles) and that's where I caught the fact that they were too tight. So I was at risk for awhile but caught it before I had to.

My convertible doesn't have a spare so I carry a compressor and a plugging kit. All my flats in 40+ years driving have been slow leaks that a compressor would temporarily resolve. A good 12V compressor is about $50 (I like Viair). I would carry it long before I would carry a 12V impact wrench.

peter gagliardi
07-15-2015, 12:12 PM
Another thought that would help. I have for about the last 25 or so years been putting copper "never seize" on my lug nut threads, AND the small cone area at the front of the lug nut that actually centers and clamps the rim . I put em on pretty tight, never, ever have I broke one, or even needed to break a sweat getting them off by hand with a normal wrench. A little lubrication amplifies the clamping force , so you don't need to crank them uber tight when you reinstall, so be mindful.

Mark Levitski
07-17-2015, 7:32 PM
Never seize on studs is a no-no according to the tire shop.

peter gagliardi
07-17-2015, 7:49 PM
Yep, but they are more than happy to hand you the bill for the labor + the broken parts. Some people always do as they've always done, well because... They've always done it!
I've done more than my share of wrenching to know what works and what don't. Everyone is free to choose their own path.;)

John Sanford
07-28-2015, 1:37 AM
Keep a 1500 watt power inverter in the trunk and a corded impact wrench. It's not the cheapest option, but it's as close to bulletproof as you can get without having an immortal trunk monkey with a 36" breaker bar. Just make sure you've tested/practiced with the setup <b>before</b> you need it.

Rick Potter
07-28-2015, 2:16 AM
Keeping up the AAA card is cheaper than a good impact wrench. Price out the nice one at SnapOn.

J.R. Rutter
07-28-2015, 9:48 AM
That 18v Milwaukee was a game changer for me when it comes to cars. I have not found a nut or bolt that it won't break loose, including subframe and axle bolts. If you are not inclined to wrench on cars, then it is expensive. But if you do, it will pay for itself after a couple of jobs. For wheel lugs, the low torque setting gets mine to the point where a half turn with the torque wrench gets them to spec. I didn't realize that they had a 12v car charger for it, so I will be ordering that for when I go to the track. I have a breaker bar in the trunk for emergencies though.

Jerry Thompson
07-28-2015, 10:55 AM
+1 on the long torque wrench. It has always been my part of any tire shop tire removal to re-torque the nuts/bolts after driving about 50 miles. On many cars the rotors can warp if the nuts/bolts are not torqued to the proper setting. This is especially true if one has to hard break and the rotors heat up.

Tim Offutt
07-28-2015, 1:37 PM
Never seize on studs is a no-no according to the tire shop.

The reason it is a no-no is because the never seize acts as a thread lubricant. Any time you are torqueing a fastener the majority of the torque applied is consumed by friction, in the threads and under the bolt or nut. A very small portion of the actual torque or rotational force applied is used to stretch the fastener and provide the clamp needed to hold the assembly together. Tension or stretch in the fastener is what holds the joint together, unless you have lock nuts or loctight.

When you introduce any lubricant, (never seize, oil, even water) the torque needed to overcome friction is reduced and the bolt stretch and/or clamp load is increased. It only takes a small amount of lubricant to allow the recommended torque to stretch the fastener to failure causing it to break. Or worse, the bolt will stretch beyond the yield point and it will break later under load.

The factories spend hundreds of thousands of dollars on equipment to properly tighten wheel lugs, which is what I sell. Unfortunately there are tire shops that still do not properly torque wheel lugs and think that tighter is better.