Bosch Impact Driver how to and troubleshooting guide
Tips & Tricks

Bosch Impact Driver How-to & Troubleshooting Guide

Bosch has an exceptional track record for making tools that perform well and are durable. For example, the Bosch impact driver has been rated the best cordless impact driver yet.

It provides the power needed when fastening screws and bolts through tough materials like concrete or masonry.

Bosch makes impact drivers with both brushless and brushed motors. However, no power tool is perfect, and they will develop issues over time.

Your impact driver may start developing issues with the power supply, trigger problems, overloading and overheating, loose driver bits, motor issues, and more.

However, with careful examination, you can diagnose the cause of the issue and determine the next action.

We have highlighted the most common problems reported by Bosch impact driver users and offered practical reasons and solutions for each problem.

How to use a Bosch impact driver

An impact driver is a handheld tool that uses rotational force and fast impact blows to drive in and loosen screws, nuts, bolts, and other threaded fasteners. Also, models differ in design, and you can use our guide below to learn how to assemble and operate any Bosch impact driver.

Charge the battery

  • Plug the charger cable into your standard power outlet, remove the protective cap on the battery and then insert it into the charger.
  • The charger’s green indicator will blink to indicate the battery is fast charging.
  • When the blinking stops, the battery is fully charged.
  • If you notice a steady green light, the battery is too hot or too cold.

Insert the application tool

  • Install the impact driver bit before inserting the battery into the tool. Next, pull the locking sleeve forward, insert the bit into the chuck up to the end, then release the locking sleeve to secure the bit.
  • Always ensure the bit is securely connected before operating the tool.

Install the battery

  • Unplug the battery once fully charged and put it into the tool handle.
  • Set the rotational direction to the middle position to avoid accidentally switching the tool on.
  • To insert the charged battery, press the release button and place the battery inside the battery compartment and release the button.
  • Reset the rotational direction.
  • The rotational direct switch changes the rotational direction of the impact driver. But you can’t adjust it when pressing the on/off switch.
  • Right rotation: Drives in fasteners. Press the rotational direction switch through to the right stop.
  • Left rotation: Loosens and unscrews fasteners. Press the switch through to the left stop.

Impact driver operation

  • Ensure your safety gear(gloves, mask, and goggles) is on.
  • Start the impact driver. Press and hold the on/off switch. The work light will turn on to illuminate the work area.
  • Note that impact drivers and drills are different. So do not use an impact driver to drill holes through surfaces.
  • During operation, hold the tool firmly and apply light, steady pressure.
  • Always hold the impact driver straight on the fastener.

Adjust the speed of the impact driver

  • Press the on/off switch to varying extents when the tool is on. Light pressure on the on/off switches results in low rotational speed, while increased pressure increases speed.
  • Alternatively, you can preselect the speed using the thumbwheel. Then, turn the thumbwheel to the desired speed. Of course, the required speed depends on material and work conditions, which you must determine by practical trials.
  • If your work area has enough lighting, you can switch off the work light by pressing the power light button.
  • To switch off the impact driver, release the on/off switch.
  • To remove the impact driver bit, remove the battery first, pull the locking sleeve forward, pull out the bit from the chuck and release the locking sleeve.

Safety tip: Always remove the battery from the impact driver before doing work such as maintenance or changing bits on the tool.

Bosch cordless impact driver keeps working.

If your impact driver keeps spinning but the chuck doesn’t, that’s an issue you can fix yourself. The issue could be related to the gears, nob, chuck, spindle transmission, or gear case. Here is an easy guide to help you identify and fix the issue.


If the internal components of the chuck are damaged, they will not grip the bits tightly and will spin on the bit itself. When this happens, the chuck is worn and needs to be replaced.

  • Take a screwdriver, remove the chuck screw, then take off the chuck.
  • Insert an Allen wrench into the chuck, then gently hit the Allen wrench with a hammer to loosen the chuck. The chuck is usually in the reverse thread.
  • Once you remove the chuck, install the new one into the spindle and hand tighten it.
  • Put the Allen wrench into the chuck and clamp it tight on the Allen wrench.
  • Continue tightening the chuck until it’s hand tight.
  • Once it fits properly, remove the Allen wrench.

Gear cases

The gear case In the impact driver comprises the transmission and the clutch. Signs of a worn gear case are when the motor spins and chuck doesn’t. There is also usually a grinding sound, which requires replacing the gear case.

To replace the gear case, you will have to dismantle the impact driver; this will vary on models as they are slightly different in design. But here is a general guide:

  • Use a screwdriver to remove the chuck screws. Then remove the handle and chuck.
  • Remove the back cover and release the tension of the brushes by moving the springs to the side.
  • Separate the two halves of the Bosch impact driver.
  • Pull the motor and gear case assembly out of the impact driver case.
  • Then separate the gear case from the motor and remove the gear selector.
  • Install a new gear selector and reassemble everything in reverse.

Bosch cordless impact driver clutch is slipping.

The clutch slip or torque control is one of the most important features in an impact driver. It is the adjustable collar located directly behind the chuck. It is numbered 1-10 or 20, representing the amount of torque or twisting power sent to the bit.

The higher the number, the higher the torque, and you can drive in larger fasteners. There are several reasons why your impact driver clutch keeps slipping; they include:

Incorrect clutch adjustment

It’s important to learn how to adjust the slip clutch properly to drive the screws to the correct depth. When driving the screw in, the slip clutch monitors the amount of torque it applies to the screw. If the force required exceeds the slip clutch settings, the clutch will slip or disengage. At this point, the chuck stops turning, but the drill motor continues running.

This is a common problem among beginners because adjusting the slip clutch appropriately takes practice, but it’s best to start with a midrange number. For instance, if your power driver has 20 clutch settings, set the clutch to 10, then the driver in a screw.

If the clutch slips before the screw are fully driven, rotate the clutch settings to a higher number. Adjust to a lower setting if the power driver drives the screw too deep.

We also recommend using the higher clutch settings to drive in large, flat fasteners and lower settings for small, thin fasteners. You should also consider the hardness of the material.

Softwoods like plywood, pine, cedar, and fir typically require little torque. In contrast, hardwoods like maple, oak, and mahogany require higher clutch settings.

Worn out chuck

Over time the chuck wears out and refuses to lock properly. Therefore the clutch will keep slipping with correct clutch settings. You will need to replace the chuck with quality parts, and cheap aftermarket chucks tend to wear out much quicker.

To replace the chuck, open the chuck jaws as far as they’d go and insert a hex key into the chuck. Then, use a mallet or hammer and hit the hex key firmly in a counterclockwise direction to twist it. The chuck will loosen on the spindle, and you can take it out and replace it with a new one.

The chuck is not tight enough.

This is common, especially for new people using drills or impact drivers. Most impact drivers and drills have a clicking noise to indicate the chuck is locked securely. You need to tighten the chuck more if you don’t hear that sound.

For other Bosch impact drill models, you may have to hear several clicks for the chuck to lock in securely. So ensure you always tighten your impact driver before running it.

Chuck is dirty

When the chuck is blocked with gunk, dust, and debris, it will not grip the bit properly. Take a moment, turn off the impact driver, remove the battery and clean the chuck with some compressed air and lubricant oil.

Ensure you clean the inside of the chuck by widening the chuck jaw and run a clean lint-free cloth inside the chuck, then pour some drops of lubricant.

The impact driver bit is inserted poorly.

Inserting the bit incorrectly into the shank will cause it to slip out when using it. So instead, take out the bit, then pull back the collet, insert the bit straight and well within the chuck, then release it.

Bosch impact drill overload protection: How does it work?

Power tools, including the Bosch impact drill, have torque overload protection features. This overload protection is a safeguard component that helps prevent the motor and battery from burning out due to overloading or overheating.

It also prevents damaging the bit and drive gears in case a jam occurs. Overload protection activates when the power tool exceeds a specific power level; the overload protection feature(torque overload protection) shuts off the machine automatically.

Bosch impact drill overload protection keeps triggering

The overload protection function is typically triggered when the impact drill is overloaded, overheated, or improperly used. When this happens continuously, release the trigger, remove the drill bill from the chuck and determine the cause of the issue.

Here are some things that trigger the overload protection and how to fix the issue.

Too much pressure

When drilling with the Bosch impact drill, you should avoid applying too much pressure on the surface. Instead, allow the tool to work itself.

When you put too much pressure, the tool’s mechanisms can’t activate; therefore, the motor has to work harder, which requires more current, thus leading to overloading.

The best solution is to allow your impact drill to cool down, then restart it and avoid using too much pressure. Do not use lighter models on hard surfaces.

Lack of ventilation

Sometimes when working with an impact drill, we cover the ventilation holes with our hands. This creates too much heat inside the tool, leading to overheating. The overheating then causes the overload protection to turn off the tool to prevent further damage.

Be aware of the ventilation holes on your impact driver, then carefully hold your tool without covering them.

Using a less powerful impact drill

Bosch impact drills come in varying torques. That means you must use the right impact drill for the right job. Sometimes when we use a less powerful tool, we put too much pressure on the tool, overloading the drill.

As a result, the tool will use its maximum efficiency and result in overheating. Therefore the overload protection will keep cutting off its power to protect the tool. The solution is to use a drill with the correct torque and RPMs for the right task.

Short electrical path

The impact drill has both mechanical and electrical components. The current leaks when the electrical path is damaged or the circuits and coils are short. This means the insufficient current will be reaching the mechanical parts.

Therefore they will have to work harder to do the same job if they are on full current supply. Due to this, the tool can overheat and trigger overload protection.

When dust goes inside the drill, it scratches the wires, causing them to sort when working. You’ll have first to disassemble the impact drill and identify the damaged wires, then replace them. In the long run, clean your tool before and after work to avoid damage to the electrical wires.

Mechanical issues

The impact drill has wheels, bearings, and shafts which rotate and touch each other. When they touch and create friction, it produces heat over time. Without dealing with the issue, the drill will overheat and activate the overload protection function.

The solution is to lubricate the mechanical parts of your drill regularly to reduce friction. Inspect the chuck for damages and replace it if necessary.

Working with breaks is also important to avoid overheating your impact drill. Another tip to prevent overheating your drill is to change the brushes every 50-60 hours of operation, or when the brush length is about a 1/4-inch long.

Incorrect drill bit angle

When woodworking, you need the right drill bit angle for efficient cutting. When the angle is wrong, the drill bit will rotate at the same spot, causing an external fire. Therefore, always use the correct drill bit angle for more efficiency.

Faulty motor

Several reasons can cause your drill’s motor to become defective, usually due to improper use of the tool for a long time. Also, the older the drill, the more likely the motor will lose its functionality. At this point, you’ll need to get a new impact drill.

Why would drill bits not work in an impact driver?

The main difference between impact driers and regular drills is torque. Impact drivers are more powerful than regular drills in fastening and loosening screws. And because of this, their bits are not identical or even interchangeable. Here are the difference and reasons you can’t use drill bits on an impact driver.

Regular drill bits are less pliable.

Impact driver bits are more flexible than drill bits, which bend easily without breaking. When fastening a screw, the impact driver bit spins at full speed and receives a lot of pressure. So using a regular drill bit on an impact driver can easily break it since it’s less pliable than the impact driver bit.

Regular drill bits have thicker shafts.

Impact driver bits have a narrower shaft than the drill bit. The narrow shaft removes excess stress from the bit’s tip and releases it into the shaft, dissipating the pressure.

As a result, it offers the impact driver bit more torsional strength than a regular drill bit. More torsional strength allows the bit to rotate without breaking.

On the other hand, the thicker shaft on regular drill bits doesn’t remove the stress from the bit tip, leading to less torsional strength. Consequently, the regular drill bit will likely break on the impact driver.

Drill bits have rounded ends.

Most regular drill bits have rounded ends which prevents them from fitting into an impact driver. While impact drivers typically work with hex bits.

However, there are some regular drill bits with hex ends; therefore, they can fit in most impact drivers. But they won’t be efficient as they can’t handle the pressure from an impact driver.

Why is my cordless Bosch impact drill not working?

There are several reasons why your Bosch impact drill stops working. Here are the most common reasons and their possible solutions


The Bosch impact drill uses a rechargeable lithium-ion battery to power its brushless motor. If the drill isn’t getting power, the first thing is to check the battery. Press the battery charge indicator button to check the charge state. The battery is defective and needs replacing if there is no LED light.

Battery charger

If the battery is in working condition and the impact drill still won’t work, you need to check the battery charger. If the charger is faulty, the battery will never get charged. Insert the battery into the charger.

If no lights turn on, the charger is not reacting to the battery connecting; therefore, it needs replacing. Ensure you get an original Bosch impact drill charger to ensure you do not damage your battery pack.

Drill chuck

The chuck in the drill holds different accessories allowing the drill to bore holes on surfaces. However, excess pressure on the bit area can cause the drill chuck to cease up.

If the bit doesn’t lock into the chuck or will not spin, then it’s a chuck problem. Remove the chuck from the drill with a flay screwdriver and replace it with a new one.


When the trigger locks up, the impact drill will not work at all. If the trigger switch burns out, you’ll need to replace it.

To replace it, remove the casing with a Philips screwdriver to expose the trigger secured inside the drill with a screw. Take out the screw, remove the trigger and replace it with a new one.

Drill motor

If nothing seems to work, you should consider a faulty motor. The electric motor in your drill is an electrical machine that converts electrical energy into mechanical energy, which rotates the drill, not the bit.

So if it becomes defective, your drill won’t work and will need replacing. The motor is located above the handle behind the chuck. Unscrew the casing, and the motor should pop out. Then install the new motor, making sure you connect the wires correctly.

How long does it take to recharge a Bosch impact drill battery?

Bosch impact drill models come in several voltages with different charging times. On average, a Bosch battery charger takes about 55 minutes to charge the 18 V 6.0 Ah battery and 25 minutes for the 18 V 2.0 Ah SlimPack battery.

This shows the charger ampere can also influence charging time. Here is a table that shows the charging time for each charger and related batteries in detail.

Bosch 12V impact drill battery charging time

Battery capacityGAL 1210 CVGAL 12V.20GAL 1230 CVGAL 12V 40CV
1.5 Ah95 min50 min35 min25 min
2.0 Ah120 min65 min45 min35 min
4.0 Ah240 min125 min85 min65 min
6.0 Ah360 min185 min135 min95 min

Bosch 18V impact drill charging time

Battery capacityAL 1814 CVGAL 18V.20GAL 18V.40GAL 186 0 CVGAL 1880 CVGAX 18V 30GAL 18V 160
1.5 Ah80 min50 min30 min25 min12 min30 min
2.0 Ah105 min65 min40 min35 min15 min45 min
4.0 Ah210 min125 min60 min45 min35 min85 min25 min
6.0 Ah180 min80 min65 min50 min45 min

Bosch ProCORE 18V impact drill battery charging time

Battery capacityGAL 1860 CVGAL 1880 CVGAL 18V 160
4.0 Ah75 min50 min50 min
8.0 Ah120 min65 min55 min
12 Ah90 min60 min

Since different Bosch impact drill models use different batteries with different capacities, you can also calculate the battery charging time using the formula below:

Charging Time (Hr) = Battery Capacity (Amh) / Charging Current (A)

Charging Time (Hr) = Battery Capacity (KWh) / Charging Power (KW)

For instance, your Bosch impact drill is 20V and 5Ah, and your charger is 20V and 5.2A current.

(20V×5Amh)/(20V×2.5A) = 2 Hrs

Note: In reality, the battery charge doesn’t ever get to 0%, so that the actual charging time will be less than the calculated time.

The charging time can also vary with environmental temperature, battery condition, and battery charging technology.

Bosch impact driver is not impacting.

The Bosch impact driver has rotational impacts with a hammer-and-anvil system which helps drive fasteners into hard materials. When using the impact driver, you will hear a noise that activates the impacting mechanism. If the impact mechanism is not there, here are the reasons:

Low battery capacity

The impact mechanisms activate when the socket is loaded. But if your battery charge runs low, the impact force will not release. Check the battery charge and recharge it.

The hammer angle is damaged.

When your impact drill is hammering, the hammer should be at the proper angle. This angle will helps slip the hammer and anvil.

Bosch impact driver is not spinning.

After using the impact driver for a long time, its spinning mechanism can stop working. Therefore you cant fasten or loosen any screws or nuts. Here are a few common reasons and some of their troubleshooting tips.

Low battery

The lithium-ion battery’s efficiency reduces over time. It gets to a point where it indicates full charge, but it’s not fully charged, thus discharging quickly when using it.

If this happens continuously, you need to replace the battery pack. Ensure your battery is fully charged before using it to avoid damaging the battery.

If the battery is in good condition, check the charger. When the charger is damaged, it will not fully charge your battery. There you will need to replace it.

Defective trigger

The trigger in your impact driver is a power switch that provides electricity to the motor, which produces mechanical power to spin the impact driver.

Usually, the RPM depends on the trigger pressing. If you put less pressure on the trigger, there is low RPM. And if we apply more pressure on the trigger, the RPM increases.

So if the impact driver is not spinning at all, it means the trigger switch has gone bad, and the motor isn’t receiving any electricity.

Also, check if the trigger is clogged with dust. Then, service and maintain the trigger to remove dirt and prevent further damage.

Worn out bearings

This is common with brushless motors. The bearing in the Bosch impact driver supports to complete the rotation of the rotor. If the bearing is worn out, it will directly affect the spinning mechanism. Inspect the bearing and replace them. It’s important to identify the issue early to avoid further damage.

Burnt winding

For brushed motors, there is a wire wrapped around the armature. Usually, when you increase the winding, the tool’s power and smoothness also increase. However, when the winding is damaged or burnt, its power reduces, and your tool won’t spin.

The motor will still work with a burned winding, but you’ll notice reduced torque. You’ll need to consult an experienced electrician to fix the winding.

After a replacement, it’s important to lubricate your tool and use an air compressor or a can of compressed air to dust it off before and after work. Sometimes dust can scratch the winding, and due to electricity running through it, it can short and burn.

Magnet crashing

Although rare in brushless models, if you drop your tool from a high point, it can break the inner magnets. This impact can break the magnetic field, affecting torque, or the tool won’t spin at all. If you recently dropped your tool and suspect it’s a magnet issue, you’ll need to take your tool to a professional.

Bosch impact driver lights are not working.

Like other power drills, the Bosch impact driver has a work LED light that lights up when your press the on/off switch lightly or fully, allowing your work area to be illuminated in poor lighting.

A common reason your Bosch impact driver work light is not working is that the bulb has burned out. Premature LED burnout could be due to poor bulb quality, overheating, and voltage jumps.

To fix this issue, ensure your battery is fully charged and connected to the impact driver correctly. If the battery is fully charged and the problem persists, replace the LED  bulb. The complexity of replacing the LED work light depends on the design of your Bosch impact driver.

How to clean and maintain a Bosch impact driver

Every tool requires occasional cleaning and maintenance to reduce repairs and increase lifespan. Here is a step-by-step guide on how to clean and maintain your Bosch impact driver.


  • Remove the battery from the impact driver before performing routine maintenance work.
  • It’s best to avoid water coming into contact with your impact driver. In addition, compressed air can eliminate dust and dirt on your impact driver.
  • Run the compressed air around the air vents, tool holder, and locking sleeve.


  • Get some standard metal oil or WD40.
  • Pen the chuck and pour a few drops of oil lubricant into the chuck without any attached bits. Open and close it several times to allow the lubricant to spread evenly in the chuck mechanism.
  • Use a soft, lint-free cloth to wipe off any excess oil. Too much oil will attract dirt and debris inside the chuck and causes blockages.
  • Install a bit and run the impact driver for about 20-30 seconds to move the oil around thoroughly.

Proper storage

  • Always keep your drill in a dry place. Avoid all types of moisture, including snow, mist, or rain, even when using your tool. Water can cause rust, leading to jamming the chuck and other moving parts, including the motor.
  • Put the impact driver in its storage case when you’re not using it to avoid exposure to moisture.
  • Also, never store the impact driver with the battery inside it.
  • Ensure that where you store your impact driver is always at room temperature(72°F). The tool can handle temperature drops of 62°F or an increase of 82°F before developing any issues. The internal parts of an impact driver wear away much quicker when the tool gets too hot or too cold.


  • Always use the right drill bit for your project. The wrong bit can ruin your work and damage parts of the drill, such as the chuck.
  • Always use sharp bits. Dull bits make the job difficult as you will have to put extra pressure on the tool. Excessive force can damage the tool.
  • Don’t overwork the tool. Take breaks when working on larger projects that take long drilling periods or on hard surfaces such as concrete, bricks, and masonry. This is to avoid overheating your tool.

Should I lubricate my Bosch impact driver?

Yes, lubrication is an important part of the routine maintenance of your Bosch impact driver. The impact driver has several moving parts that produce friction. In turn, the fiction can cause overheating and wear of these components.

The oil helps to displace moisture and keeps gears and motors cooler. You can use Bosch’s Worm Drive lubricant, which is suitable for drive mechanisms.

Bosch 12v impact driver is not working.

Below are the most common problems with the 12V Bosch impact driver.

Low battery

These Bosch impact drivers come with 12V battery packs. The trigger won’t activate the motor if the battery pack is not charged. Try charging the battery for one hour.

Faulty battery

If charging the battery pack doesn’t work, the battery or the charger may be faulty. If the red indicator light on the charger blinks, the battery is defective and needs changing. If there are no lights on the charger, then the charger is bad and needs a replacement.

Trigger is faulty

The impact driver has a trigger switch that activates the electric motor to turn the rotating chuck. If the trigger is still not working after the previous steps, the trigger must be faulty and needs to be replaced. Follow the instructions below to replace the trigger on a 12V Bosch impact driver.

  • Remove the battery before attempting to replace the trigger to ensure the impact driver doesn’t accidentally start.
  • With the battery compartment open, locate the clip that connects the two halves of the outer casing on the back edge of the battery compartment.
  • Then use angled tweezers to remove the clip.
  • Find the eight 5.5 mm screws on the drill’s upside half.
  • Remove each screw and remove the casing to expose the motor and trigger.
  • Place a finger under the metal tab and lift it gently to release the trigger mechanism.
  • Remove the trigger mechanism carefully from the tool and disconnect the two wires connecting the motor to the trigger with some pliers.
  • Install the new trigger and reassemble the impact driver in reverse.

Faulty clutch

If the adjustable clutch doesn’t rotate and is stuck, you will need to replace the gearbox.

Defective motor

The motor must be faulty if none of the solutions above get your impact driver working. Then, you can replace the motor or the entire impact driver with a new one.

Which should I get, 12V or 18V Bosch impact driver?

It depends on what you want the impact driver for. There are significant differences between the 12V and 18V models that you need to consider to make the decision. Here is the guide below.


The 18V impact driver has more power than the 12V models, meaning they are more powerful. As a result, the 18V impact drivers are better for demanding jobs or dealing with harder materials.

However, model 12V impact drills with lithium-ion batteries can provide as much power as the 18V impact driver, if not more.


The 12V impact driver models are significantly lighter than the 18V models. As a result, they are the best tools to use when working in small spaces such as attics, crawlspaces, or when working overhead with your arms stretched.


If you want a smaller-sized cordless impact driver that can fit in your storage box, choose a 12V Bosch impact driver model. If space or mobility is not an issue for you, you can go for the 18V models as they are bulkier.

Charging time

The 12V Bosch impact driver range charges faster than the 18V models. This is because the 12V tools have smaller batteries and less capacity, so they charge faster.

However, with the fast-charging technology in Bosch battery chargers, the 18V impact drivers could take as much time as the 12V tools to charge. Also, the run time depends on the battery capacity.

Therefore a 12V impact driver with a large capacity battery could have a longer charging time than an 18V impact driver with a smaller battery capacity.

Run time

Given the same task, 18V Bosch impact drivers will run for longer on a single charge than the 12V range. Therefore, they are best to use when you have larger projects. However, battery capacity also affects run time.

If your 12V tool has a battery with more amperes than the 18V, the difference may not be that significant.


18V Bosch impact drivers tend to be pricier than the 12V range because they are bigger, heavier, more powerful, and with a longer-lasting battery.


To summarize this guide to Bosch impact driver troubleshooting, always remember to store and use your tool away from moisture and heat. Proper maintenance will reduce breakdowns and ensure your tool serves you efficiently and for longer.