Milwaukee M12 impact drivers have various reported problems if you look online. While checking up on some of them, I saw a few that are so common especially.
Today I want to talk about them and help users stay ready if they encounter them. Go over this list with me to learn about troubleshooting common Milwaukee M12 impact driver problems.
I also have here a short video about the components you need to check on your Milwaukee M12 impact driver for common problems. You can watch it below.
After opening my Milwaukee M12 impact driver, I checked its trigger, forward/reverse button, wire connection, battery, brushless motor, and lastly the gear and impact mechanism.
Troubleshooting 5 Common Milwaukee M12 Impact Driver Problems
- Milwaukee M12 Impact Driver Not Spinning
When it comes to this particular tool not spinning, I think the collet is to blame. There’s a common defect with these collets that I’ll talk about later, but for now, I mean more general issues.
A big example of that is just a plain, dirty collet. Dirty collets that have debris covering their crevices can stop impact drivers from spinning as there’s no room for the bit to move.
That’s usually the best case scenario though, since it’s so easy to clean the collet. Just get the screwdriver bit out of there like I have from my collet in the photo below. Clean the inside thoroughly afterward.
Collets can also break down after a while. This makes them restrict the screwdriver bit and causes issues with spinning. Ensure there’s no damage on yours if cleaning it didn’t work.
Replacing the collet should do the trick, and the Milwaukee M12 impact driver will spin normally again. Just make sure to get good quality collets to avoid regular issues.
I have a video below which you can watch. It shows how a perfectly working Milwaukee M12 Impact Driver puts a screw into hardwood.
- Milwaukee M12 Battery Acting Up
When I was doing research for this guide, I saw all kinds of complaints about the Milwaukee M12 impact driver’s battery. From complaints about battery life to much more, let’s just say it’s got issues.
Don’t get me wrong, though. None of these common issues are without reason. They’re just a part of any battery’s life cycle, as they get weaker with time.
Before I talk about those, one thing you can actually avoid is overheating. This occurs when users push the battery too hard, keep it in use too often, or leave it in hot areas.
Whenever the Milwaukee M12 battery is overheating, the charger will start flashing red. You can see this battery I’m charging below, which is overheating too.
Dealing with overheating batteries is as easy as unplugging the battery out of all tools. Keep it in a cool area, and set it aside until it gets back to normal temperatures.
As for other common Milwaukee M12 impact driver battery issues, there’s low capacity. This is unavoidable after a few years of use, along with most other battery complications.
Troubleshooting them isn’t exactly possible. You can try changing internal cells, repairing circuit boards, and other stuff. But, at the end of the day, the best way to deal with an old faulty battery is to replace it.
But before you buy a new Milwaukee M12 battery you can first try to reset it. I have a video below which shows how to do it.
My Milwaukee battery has a charging issue and the indicator lights on the charger shows a blinking red and green light. This means my Milwaukee battery is not healthy anymore.
To reset this battery, you would need another healthy battery with similar specs. Connect the positive and negative terminals of the two batteries using two wires.
Leave for around 15 seconds and then disconnect them. Then, try to recharge your faulty battery again on the Milwaukee charger and it should now be charging properly.
You know, it’s very important that you know the meanings of the different indicator lights on the Milwaukee M12 battery. I have made a short video about this topic and you can watch it below.
If you see a solid red, it means the battery is charging normally. This will turn into a solid green when the battery becomes fully charged.
As previously mentioned, a flashing red and green means it has detected a bad battery. If you only see a flashing red, it means a hot/cold relay.
- Blocked Temperature Sensor
A surprisingly common complaint about the Milwaukee M12 impact driver is how it randomly doesn’t work. So many users are confused by it, and it was surprising to see how common this is.
After I did some tinkering, I now know the reason for it. It apparently has to do with the sensor on the terminals of a Milwaukee M12 impact driver battery. One of these is terminals for the temperature.
When something blocks that terminal, it stops the tool from turning on. That’s because the impact driver can’t tell the temperature of the battery, making it believe it isn’t safe to use.
Cleaning around that terminal is enough to fix this. If you aren’t sure which one I’m talking about, I’ll highlight it in the image down here so you know.
After you clean the terminal, the tool should start working again. But, if it doesn’t do the trick, try to clean around the area of your Milwaukee M12 impact driver where the battery sits.
Use something to get deep inside that spot and clean around it. Use a flashlight to get a look at the metal terminals inside and clean those especially.
- Milwaukee M12 Impact Driver Collet Problem
The collet problem is one of the more infamous things about the Milwaukee M12 impact driver. It’s a really common problem that completely stops the tool from holding bits of any kind.
This problem happens because of a bad spring deep inside the collet. I even mentioned it at the start of the troubleshooting list, and now I’ll focus on it.
To fix this mess, you have to remove all the rings around the collet and get to the specific ring at the very bottom that’s problematic like I’m doing in this photo:
After reaching the bottom spring, notice that it has bending/curving. That’s what stops the collet from holding bits. Users need a similar spring without issues to replace it.
I have a much more detailed guide on this entire procedure which you can check out. It’ll walk you through the whole process step by step, and help the collet get back to form!
- Driver Stop In The Middle of Operation
Whenever an impact driver suddenly starts stopping during the middle of a job, stop using it immediately. Instead of doing whatever you’re doing, just use it freely in the air.
Does it keep spinning without any problems without stopping? If the answer’s yes, that means the Milwaukee 12 impact driver is being used for something it can’t handle.
There’s a limit to the workloads these tools can handle. If you exceed that, the failsafe inside will activate and stop it in the middle of use. This is done to prevent major damage.
There’s not much troubleshooting to do about this. But, I figured I would add this at the end since it’s still something users commonly complain about.
Limitations like that are impossible to bypass. If users try to use the Milwaukee M12 impact driver for something it can’t handle, it obviously won’t get the job done.
Try not to exceed the work limit, and don’t push the tool too hard if it keeps stopping in the middle of use!
