How to Oil an Impact Wrench – Step by Step Guide

How to Oil an Impact Wrench – Step by Step Guide

Apparently, there is an old saying that goes “An ounce of prevention is worth a pound of cure.”.

The act of cleaning your tools is not just a convenience – it’s a smart move. It is imperative to keep your tools clean and maintained, regardless of whether you are a professional or a DIY handyman. Manufacturers typically include a user guide with each impact wrench set they sell, but maintenance instructions are rarely included.

We have put together this guide to help you figure out what is the best method for cleaning an impact wrench and how to oil an impact wrench.  

How to oil an impact wrench

Why is it Important to Oil Impact Wrench?

Lubricating your impact wrench regularly is a good idea since the more often you use it, the more dust will accumulate inside it. Does your impact wrench seem a bit rusty? If you have a lubrication regimen in place, you’ll notice a difference. Maintaining your air tools properly will prevent lock-ups or stalls, increase tool life, and ensure peak performance throughout the tool’s lifetime. There are times when greasing can restore functionalities to worn-out or non-functional tools. A simple maintenance procedure can make a significant difference.

how to oil an impact wrench
how to oil an impact wrench

In the air impact wrench, there are rotating parts that serve the purpose of loosening and tightening machine nuts. The mechanism should be kept oiled to prevent loud noises. Trash inside the wrench can also cause problems. As you know, the tools come pre-oiled when you buy them, but sometimes they need to be cleaned in order to function properly. Using the tool in the correct way will ensure smooth operation and avoid clogging. Thus, you should always lubricate it correctly.

What Causes Air Tool Degradation?

When contaminants, such as water, dirt, rust, and other material are allowed to stay on these surfaces for a long period of time, they will quickly erode them, destabilizing your motor’s performance and reducing its lifespan. The motor of your air tool is made up of machine-polished surfaces, much like the engine of your car. If the airline of your impact wrench is contaminated with water or condensation, it can seriously affect the performance and longevity of the tool. Make sure your air tool is well oiled with pneumatic air oil.

What things do you need to Clean and Maintain your Impact Wrench?

If you are a beginner, it’s important that you take extra caution to protect the motor casing and any exposed parts of the machinery as well as any cables when cleaning your power tools. Here are some tips to keep you safe when cleaning or lubricating power tools.

  • To reach sensitive and hidden areas, always use a toothpick or Q-tip.
  • You’ll be wearing gloves and boots to protect your body
  • Take advantage of your cleaner and use it to clean power tools.
  • It’s advisable not to soak it in liquid, since this can damage the motor and electrical components.
  • You should always keep the tool manufacturer’s guide on hand.

This method requires the use of:

  • Bucket
  • Soft rag
  • WD40 or 4 in 1 oil
  • Toothpicks / Q-tips
  • Wire brush or steel wool
  • Air compressor or a can of compressed air
  • Degreaser or a similar cleaning agent

Before Oiling, you need to clean your Impact Wrench – Here is the process

Taking the time to completely clean the air impact wrench correctly is very important before beginning the lubrication procedure. It is useless to lubricate the mechanism with garbage. Additionally, neglecting to clean up junk eventually damages your tool. In order for the tool to do its best, you must clean it thoroughly on a regular basis.

How to clean your Impact Wrench?

Disconnect Power

In order to avoid being harmed by electrical shock, always remove any batteries or power sources from the tool


The first step is to remove the rubber jacket on top. Once that is done, there is a plate on the back. Remove the nuts attached to it. Remove the alignment rod. Tap the anvil with a hammer and remove the bearing from the back using a punch tool. If you begin at the front to remove the anvil and hammer together, you can remove them at once.

Use an Air compressor

You can use compressed air or an air compressor through an air hose to remove any dust or debris. A buildup may occur behind certain areas that are difficult to see.

Make a cleaning solution

Pour warm water halfway into a bucket. Next, add your cleaner.

how to clean impact wrench

Start cleaning

The best way to remove rust is to use a wire brush and steel wool using a cleaning solution. When scrubbing, it is important to be careful, otherwise, you may damage the tool.

Clean thoroughly

With a toothpick or Q-tip, you will be able to maneuver into the narrow nooks and crannies of the vents and recesses with greater ease. Afterward, you can wipe the area thoroughly with a soft cloth if needed.

Replace damaged parts

If the grips are seriously damaged, you may want to replace them. Cleaning them with this method leaves them greasy-free and perfectly clean.

Don’t forget to clean the power cords

Apply some of the cleaners to a rag, and then run the cords through it. When you are done with this, make sure that you let them dry completely before plugging them in again.


In order to reassemble everything correctly, you need to do it in the reverse order of how you removed it initially. Do not rush the reassembling process. It will take a lot of time otherwise to get everything back in order.

Lubricating your Impact Wrench (Air and Corded/Cordless)- The complete process

Impact wrenches can be operated either by electricity, battery, or compressed air. It is not difficult to perform routine maintenance and lubrication on your impact wrench, as it hardly takes any time or effort. The moving parts of air impact wrenches must be lubricated periodically, unlike electric impact wrenches, which are usually equipped with sealed motors. Below are some tips on how to oil an air, corded and cordless impact wrench properly.

There is a two-way lubrication method for the impact wrench:

  • Grease lubrication method
  • Oil bath lubrication method

1. Grease Lubrication Method

Every 48 hours of tool runtime, it is important to grease the impact mechanism, specifically the hammer and anvil. It is possible to hear a lot of noise from the mechanism if this run time is exceeded during operation. This can lead to a decrease in the performance of the mechanism and possibly even damage it.

Remove the hammer case

To begin, remove the hammer case bolts. The hammer case can be removed by removing the tool from the front, setting the tool in the back, and using the anvil to hold it in place, lifting the tool.

Removing hammer pins

To remove the hammers from the hammer frame, simply remove the hammer pins and slide in the hammers.

Wipe the old grease

Use a clean rag to wipe the old grease off the Hammer’s anvil hammer frame and hammer case.

Apply grease

Grease the hammer and its frame with a light coating of grease. Lubricate the anvil lugs and the bushing portion of the anvil liberally with grease.


Put the anvil back into the hammer frame. Always remember the gasket’s location and orientation of all the components.

Wipe excess grease

To remove any excess grease, torque the hammer case bolts. Wipe any excess grease from outside of the tool. Examine the anvil to make sure it is free to move.

2. Oil Lubrication Method:

Oiling the air motor and hammer are two major parts to take care of. You can follow these steps:

Locate and remove the oil port

Take off the oil plug on the oil inlet port with the 4mm Allen key. Here is where you will introduce oil into the wrench.

Lubricate the hammer mechanism

Fill the oil port with approximately one ounce of oil, using the appropriate tool.

In this way, lubrication will be provided to the hammer mechanism.

Lubricate the air motor

Fill the air inlet with 6 to 7 drops of oil These drops will lubricate the air motor and its bearings.

Run the impact wrench

Run it for a couple of seconds. By running the tool at the low throttle for a couple of seconds without the load, distribute the oil evenly throughout the machine.

Drain and wipe excess oil

After draining the excessive oil, wipe the housing and exterior with a dry cloth after removing the oil plug.

Reasemble the wrench

If you had previously removed the rubber jacket or another component, replace it carefully. After good oiling, you’re ready to use your impact wrench once again.

What kind of oil do you use in an Air, Electric and Cordless Impact Wrench?

Oil for an impact wrench tends to be thinner and contains additives that prevent the rusting of the tool. It is advisable to use anti-corrosion light oils such as SAE #10 and #30, for electric and cordless impact wrenches, since they contain corrosion inhibitors. It is best to use an air tool oil that contains anti-foaming and other gumming agents for an air impact wrench. Such as an impact gun oil formulated specifically for air tools or mineral oil.

How much oil do I put in an Impact wrench?

Furthermore, there is one more thing that should be kept in mind. When it comes to the procedure of impact wrench maintenance, you need to remain calm and careful. Do not rush when putting in the oil. It is necessary that you use the right amount of oil depending on the condition of the machine. The amount of oil it needs might depend on when you bought it and how long ago you bought it. A good rule of thumb is to stop every three or four drops of oil and start over again.

How often should you Oil your Air, Corded and Cordless Impact Wrench?

Using a cordless wrench frequently, such as three or four times per week or at least on a regular basis, can make it necessary to use oil more often. The same goes for air impact wrenches. Experts recommend lubricating an air impact wrench every eight hours. Electric impact wrenches should, however, be lubricated after 48 hours of use. As the night wears on, lubrication prevents condensation that would otherwise cause rust to form. It is, therefore, better to set the lubrication regimen based on the usage.

Should I grease the inside of my Air Impact Wrench?

It is important to regularly replace the grease in the system to prevent gunk build-up. For most people, this is something they do every eight to ten hours. You should use cordless impact wrench grease to protect the anvil (the area that touches the hammer) and the inner area of the hammer with either a brush or your fingers.

Which parts of an Impact Wrench need Lubricating?

To lubricate the wrench, pay attention to these two parts:

a. Motor

b. Impact mechanism

What are the consequences of not lubricating correctly?

In the case of an impact wrench deprived of grease, the internal components will wear down, resulting in a shorter life expectancy for the impact wrench. When grease is not routinely added to the impact mechanism, it becomes much more susceptible to failure. Both grease mechanisms and oil batch mechanisms can be expected to last for the same amount of time if lubrication is applied correctly and regularly.


Taking a few minutes to clean and oiling air tools you use regularly, will undoubtedly prolong their life. By keeping your tools clean, you will prolong their life and save money by not having to replace them as often.

Regularly lubricating your tools with air tool oil will not only make them look new, but they will also function at their best. Use the air inlet to lubricate the impact wrench daily (or before each use). During continuous operation, re-oil it every 1 to 2 hours.

Bahram Shahab
Bahram here! A certified Electrical Engineer who knows his way around using power tools like a professional. My journey of using these robust tools started back when I graduated. Since then, I have finished almost a dozen DIY woodworking jobs. Apart from that, I have developed this habit of jotting down my personal experience about using a specific tool. So, I write on them to help the community in the best possible way.