Looking on feedback on impact wrenches--corded, cordless, pneumatic

I was wondering about getting an impact wrench to deal with rusted-on fasteners on the underbody. I do not–at present–have a source of compressed air, so I was looking into electric impacts, both corded and the new cordless ones.

The consensus I got is that cordless are basically “wannabees” that are good for light-duty stuff, but don’t comapre when used on rust-welded bolts that haven’t turned in decades.

But what about corded ones? I saw a DeWalt once that looked pretty stout–are these a reasonable option for my needs, or do I have to save for an air compre$$or and associated tools?

Corded is better than cordless.
Compressed air is better than corded.

Be sure you get an impact wrench of decent torque value.
Be sure you get a compressor of sufficient size to drive the impact wrench.
You’ll not regret spending the extra cash.

“rusted on fasteners on the underbody”…are you starting a major project? What, exactly, are you wanting to do? Might renting a good setup work?

Is this the only thing you’re going to run? What I mean is, do you have a need for a compressor stout enough to run pneumatic tools for anything other than this project?

If the answer is no then just get the corded electric model. I have a compressor but have used electric impacts in the past with great success.

Before you get any of them, spray PB blaster on the bolts, wait 24 hours, spray it again, and then use a nice long breaker bar on your non-ratcheting box wrench. This is, of course, assuming that the fasteners are in such an orientation that you can get a breaker bar in there.

I’m not advising against getting impact tools, but you should buy them with the idea of having and using them for years to come, not for just one project. If you can get through these bolts with the breaker bar setup, then you can save money and get a good air compressor (no oilless plastic-geared junk - get a good one, at least 20 gallons, at least 110psi, and at least in the neighborhood of 5CFM) with a basic set of tools (ratchet, impact wrench, chisel, blow gun, and tire chuck would be a very good starter set). You’ll find yourself using it quite a bit if you do much car work at all.

An impact wrench is a great tool for loosening rusted bolts. Where a breaker bar even with penetrating oil applied to the threads may sometimes break a corroded threaded fastener, an impact wrench will loosen the fastener. My impact wrench is air operated but I suspect that an electric impact wrench will do the job because many rusted bolts and nuts do not require full power applied with the air wrench. It is possible that a 120 volt electric wrench is fully as capable as an air operated wrench but I don’t know that. I use my inexpensive impact wrench at a very low setting to reliably loosen brake bleeder valves among other things.

If you do get an air operated wrench, you do not need a large compressor unless you have a vehicle repair business; just an air storage tank that will hold enough air for bursts of impact wrench use for one bolt at time.

You will never regret owning an air compressor outfit if you decide to go in that direction. Mine is homemade with scavenged components; put together for little money.

I recently bought an air compressor for my home garage and have never once regretted it. The one I bought is small and light enough to take with me if I have to go to a friend’s house to help them with their car issues, but big enough to run any of the air tools I have. This is the one I bought, and it is amazingly good quality for the money: http://www.harborfreight.com/25-hp-21-gallon-125-psi-cast-iron-vertical-air-compressor-67847.html

For impact wrenches, cordless ones are only good if you spend an arm and a leg on them. A former coworker of mine bought one off the Snap-On truck for around $400 and it was pretty stout, almost as strong as an air powered one and the battery would usually last most of the day before needing to be charged. On the other hand, I bought one for $50 and it was junk. Couldn’t even loosen properly torqued lug nuts with it. Corded ones are pretty nice. I have used them a couple times, but much prefer my air powered ones. I currently have an older Matco impact wrench, but it is well worn and tired. I will probably give this one a try: http://www.harborfreight.com/12-professional-air-impact-wrench-68424.html 700 foot pounds ought to be strong enough for almost anything.

I have an Ingersoll Rand 231 C ½" drive pneumatic model. I’ve never regretted buying it. It will instantly break nuts loose that the cheaper models won’t budge.

If you do any kind of DIY work on your car, a good air compressor is worth it. Home Depot has some decent oil-lubricated ones for a bit over $400. Once you have one, you’ll wonder what you did without it. Even for something as simple as inflating a ball or topping up a tire, it’s really nice to be able to just grab an air hose and do it.

I have a 1/2" corded Kobalt model from Lowes and it works pretty good. It works better than any of the cheap 3/8 or even 1/2" air powered wrenches. Note: I said cheap. the Kobalt is rated for 400 ft lbs where a lot of the cheap air powered units top out at around 350. So far I haven’t run across a bolt it couldn’t handle.

If you go air powered, go with Ingersol Rand and get a good compressor. They have a 1/2" wrench that will give you up to 1100 ft lbs of torque.

Just a word on compressors…If you decide to get one, go for a good oil-lubed one…You know, the ones that have the big, belt driven flywheel on the pump. The oil-free and oil-lubed models that are direct-drive from the motor are obnoxiously loud. It makes a big difference after a while, especially if you decide to do your brakes at 7:00 AM. Home depot has a 30 gallon Husky that you can roll around like an appliance dolly. For DIY work, an impact wrench is usually used in spurts, but if you get into grinders and cut-off tools, you’ll want at least 5 CFM @ 90 PSI. 10 is better.

You can actually hold a conversation in the same room with this one while it is running.


You can have an impact driver kit for $15. It uses brute force (a hammer). It works for me, and is my favorite tool. Remember that thread last year? Here’s the one I bought:


It may work for you, and you could save enough money for a seat at a Steelers game.

Dewalt DW293 is a 1/2" electric corded impact. Good tool IMO

I have a cheap air one. It is good for most jobs but if you are breaking rusted bolts of any size, you really need a big one. Its good though for speeding assembly and disassembly though but sometimes need to break the bolt loose first. If you don’t have a compressor, the electric would be your only other option but check the rating on it and don’t expect it to loosen stuck truck bolts.

I’ve had one like this for ~25 years:


It’s oil lubed and yes, it’s noisier than the belt driven ones, but a 50ft hose and a second tank take care of that.
I can easily lift it by myself and put in the back of my small hatchback cars.
I change the oil every 10 years and I had to replace the motor capacitor a few years ago.

I wouldn’t purchase a compressor just to run a impact driver. They do come in handy for doing other things though. If you get a half inch corded model I’m sure you will like it a lot and will do about any job you have for it. If you don’t need to use it more than a few times a month you could most likely get by with a cheap Harbor Freight model just fine.

I prefer the belt driven models. They seem to be reasonably priced at Harbor Freight and Tractor Supply. If you ever get one you’ll wonder how you ever did without it.

Thanks. I need an impact wrench because of rusted-on bolts for balljoints, etc…I’ve actually bent combination wrenchs without budging bolts before!

I had an air setup–briefly–that I had to sell in hard times. I just wondered if a corded one would work. It’d be a lot more convenient for work away from home, as opposed to lugging an air compressor around!

Since the subject has come up, I’ve never really understood what about the compressor is most important for getting full torque out of an air impact. I have an impact that tells me that it will do 525 ftlb. However, I’m assuming that getting the full power from it requires the right oomph from the compressor - or does it not? Compressors have all of these specs - there’s the tank capacity; motor hp; max psi; X cfm @ X psi… Which, if any of those, is most important to getting full torque from an impact.

On the compressor end, Having a regulator that supplies enough instantaneous flow at the required pressure. I think most of it is how well designed and maintained the tool is. For tools like grinders that are used more continuously, the pump has to be able to supply enough air to keep the pressure up. Impact wrenches are used in spurts, so they usually don’t need much from the pump.

As an auto mechanic, I recently got sick of having the air hose in the way all the time, so I just bought a slew of cordless power tools. For impact wrenches I went with Milwaukee. Their 1/2" drive 2663 model has 450 ft lbs of advertised torque & it seems to produce that much in my opinion. Cordless power tools are not the pathetic weaklings they used to be, let me tell you! Also, I’m not sure corded impact wrenches, on the average, are stronger than cordless anymore.

At the shop I would say more than 9 times in 10, my 2663 has enough strength. I put 4 tires on an F350 Super Duty the other week. Lug nut spec was 165 ft lbs. I also have the Milwaukee 2664 3/4" drive cordless impact wrench rated at 500 ft lbs working torque. What a beast! If i was working in my own garage or driveway, the cord on a corded power tool would drive me nuts, getting tangled around your leg, etc. Cordless tools are so handy. I will admit that the max torque is gotten from air tools.

If anyone can show me a corded 1/2" drive impact wrench stronger than the cordless Milwaukee 2663 (450 ft lb working torque), the cordless Snap On CT6855 (400 ft lb working torque), the cordless Matco MCL18IWVS (425 Ft lb working torque), or the soon to be released cordless Snap On CT7850 (450 ft lb working torque), please let me know. By the way, breakaway torque will always be higher than working torque, but is difficult to measure accurately, possibly why some manufacturers don’t give this spec.

I just hate electric cords; personal problem, maybe.