How to Oil Impact Wrench

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Your impact wrench requires regular oiling. However, many people do not know how to go about it, or even what type of oil to use. So, how do you put oil into the tool? Read this short guide to learn how to oil impact wrench parts easily in a few simple steps. 

How to Oil Impact Wrench

In this guide you will learn why it is important to oil an impact wrench, the parts to focus on when to oil, and the exact steps to follow. 

Let’s dive in. 

What you Need

  • Motor oil 
  • Air tool oil 
  • Petrol (or spirit depending on availability and preference)
  • Hex Key to remove and replace fasteners
  • A punch and hammer to position parts
  • Sizeable compressed air to run the impact wrench and distribute oil
  • Rag to wipe off excess oil
  • A pan to catch excess oil
Motor oil

Step 1: Disassemble The Impact Wrench

After using your impact wrench for some time, it will have accumulated dirt and metal chips from the rotating parts. Start by cleaning it to remove dirt and contaminants. To do that, you will first need to disassemble the impact wrench. Follow the steps below:

  1. Remove the rubber jacket if it has one. If yours does not, skip to the next step.
  2. Take out the backplate and its gasket
  3. Place the gasket that seals the backplate safely so it doesn’t get scratched.
  4. Remove the alignment rod and keep it in a safe place.
  5. Next, remove the air motor.
  6. Remove the air motor housing. Remove the front bearings, too. 
  7. Remove the hammer together with the anvil by pushing ok the anvil’s front. Separate the two parts after removal. 

Step 2: Clean the Impact Wrench Parts

After disassembly, it’s now time to clean the different components. An impact wrench utilizes a lot of torque, which taxes the different parts of the tool. This will make your oiling effective as the oil will remain functional for a long time.

  1. Using gas or spirit, wipe every part to remove dirt and any solidified matter on their surfaces.
  2. Make sure that you clean the moving parts properly to remove metal chips.
  3. Clean the air motor vanes too. These are likely to be covered by dust and grime.

Step 3: Re-assemble the Impact Wrench

After cleaning the impact wrench parts, put them back together so you can oil them. Use these steps to do that.

Impact wrench beside a wooden pallet
  1. Start by attaching the hammer to the anvil. Ensure that you use a gasket. 
  2. Place the anvil-hammer assembly into the impact wrench casing.
  3. Replace the bearing.
  4. Position the air motor inside its housing.
  5. Smear the air motor vanes with air tool oil to prevent them from rusting.
  6. Replace the back bearings.
  7. Using an align rod, position the impact wrench’s back bearings.
  8. Replace the gasket that seals the backplate.
  9. Attach using the backplate and the nuts that hold it in place.

Step 4: Oil the Impact Wrench 

There are two major parts that need oiling: the hammer, and the air motor. Check the wrench’s side and find the oil inlet port. This is the opening that you will use to introduce oil into the wrench. Then, follow these steps: 

  1. Using the 4mm Allen key, remove the oil plug on the oil inlet port
  2. Using a syringe or any other appropriate tool, pour about 29 ml or 1 ounce of motor oil into the oil port opening. This will help lubricate the hammer mechanism
  3. Squeeze 6 to 7 drops of air tool oil into the air inlet port. The oil will lubricate the air motor and its vanes to ensure their proper operation and prevent damage
  4. Start and run the impact wrench. Rev it for a few seconds (around half a minute). This will help distribute the oil inside the hammer and air mechanism assemblies.
  5. Next, remove the oil plug and drain the excess oil from the impact wrench. Have a pan ready to hold the oil. 
  6. Wipe the impact wrench body with a rag to remove spilled oil from its exterior
  7. Replace the rubber jacket that you had earlier removed. Your impact wrench is now all oiled and ready to use again.

Why Do You Need to Oil Your Impact Wrench?

An impact wrench contains moving components which, if left unlubricated, could easily get damaged. The tool also uses an exposed motor that could get rusted from contact with moisture. In short, oiling your impact wrench helps to ensure: 

Impact wrench cleaned with oil
  • Smooth performance 
  • Reduced friction and wear
  • That the metal parts do not rust from exposure to moisture

Two components require oiling in an impact wrench; the motor and the rotating hammer. These two parts are subjected to rotation and need constant lubricating. They are also usually exposed to moisture-containing air and prone to corrosion. 

Impact wrenches come already lubed by the manufacturer. However, the oil tends to evaporate over time, especially with regular use. That is why you need to replace it or the tool may not last its lifetime.

When to Oil an Impact Wrench

Many people want to know when it’s most appropriate to oil their impact wrenches. However, there’s no specific time to do this. It depends on how frequently you use the tool and how long you have been using it.  

If you are a regular user, we recommend squeezing a few drops of motor and air tool oil air tool before and after every use. Doing so ensures the smooth performance of the moving parts. It also helps with preventing corrosion during storage.

For impact wrenches that need using many times in a day, it’s essential to oil them every few hours. This is to ensure the moving parts remain lubed and working properly. If your usage of the tool is occasional,  ensure to oil it every month. 

Conclusion

You now understand how to clean and oil your impact wrench at home. For best results, use the steps in this guide correctly. Impact wrenches need regular oiling, or they will not perform to your expectations. Also, note that Impact wrenches and most power drills are responsible for about 5,800 hospital visits every year. So, you need to be careful when handling them. 

An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.