How to Rebuild an Impact Wrench

Sometime during your construction or automotive career you will have to rebuild your impact wrench.  This may seem like a daunting endeavor because there are many different brands and styles. Sometimes called an air wrench, an impactor, air gun, or a torque gun, the main assembly is similarly rebuilt across the different brands and styles.  

Supplies:

• Solvent


• Light grease (IR 115 grease works the best)        


• A torx driver set with the correct size bit

How to rebuild the impact wrench:

1. Remove the outer hammer casing, the 4 torx screws are usually found on the back.


2. Remove the internal hammer and use the solvent to thoroughly clean the assembly and allow it to dry.


3. Cover the internal hammer with a small amount of grease.


4. Locate and remove the veins of the air motor, clean them using solvent.


5. Use a small amount of grease to coat the veins then replace them.


6. Check the tip valve in the handle to remove any debris.


7. Assemble the impact wrench and test before use.

Things to look for while the wrench is disassembled:

1. Note the condition of the anvil, which is a square piece that acts as a driver inside of the metal case. If the anvils are cracked you need to replace them.


2. If the vanes in the motor are concave shaped then they are worn out and are easily replaced using a vane and seal tune up kit.


3. Finally, check the air hoses fitting attachment to ensure there are no leaks.