How to Maintain an Impact Wrench

Maintain your impact wrench properly and it will last for a long time.

Impact wrenches are pneumatic, socket-wrench power tools. These tools provide high-torque output without much effort expended by the user. Impact wrenches store up energy in a rotating mass and release that energy suddenly through the output shaft. Most impact wrenches are powered by an air compressor, but some use electricity or hydraulic power. Impact wrenches are used in almost all auto repair shops, and are also used to maintain heavy equipment, on assembly lines and on some construction sites. These wrenches are available in all socket sizes.

Instructions

1. Check the impact wrench at the end of each day for debris. Debris causes air tools to lock up, scar and pit metal parts. It also reduces power.

2. Use an air dryer or inline filter and water separator at the end of each day to remove moisture, dust and corrosive fumes from the wrench. Moisture causes rust and damages the cylinder, rotor, vanes and end plates. Drain the water separator every day.

3. Oil the impact wrench at the end of each day. Use an inline oiler or oil by hand. Inline oilers are installed between the air valve and regulator to oil the impact wrench during use. Use a non-detergent oil. Apply the oil through the air inlet and run the wrench for 30 seconds to one minute to circulate the oil. Allow the wrench to sit overnight to ensure the oil penetrates all moving parts.

4. Inspect the impact wrench once a week. Run it in both directions. Tighten a nut into a stud with the wrench. Begin removing the nut with a torque wrench and determine the torque required to loosen the nut. If the proper amount of torque was not achieved, the impact wrench probably needs rebuilding.

5. Check the clutch lubricant once per week. Most impact wrenches have either a pin clutch or a twin-hammer design. Consult your owner's manual to determine which type you have and how to lubricate the clutch. Add only the amount and type of lubricant recommended by the manufacturer.

Tips & Warnings

• Read the owner's manual for your impact wrench and follow instructions for care and maintenance. Keep the manual handy.

• Use liquid pipe sealant when attaching whip hoses to prevent leaks.

• If you use Teflon tape to attach whip hoses, avoid putting it on the last two threads. The tape can flake off and damage the motor. Whip hoses are used to attach the air compressor to the wrench to prevent over-stressing the air line connector or plug.

• Use protective covers to protect the housing and never leave the wrench out where a vehicle can drive over it.

• Maintain the air compressor properly for proper air tool operation. If air pressure drops lower than 90 psi during operation, the wrench may not achieve optimal torque.

• Never drag an impact wrench by the cord.

References

• Tech Tire Repairs; Vol 26, Iss 1; Impact Wrench Use and Maintenance; 2002
• Normark Industries, Inc.; Impact Wrench Use and Maintenance; 1999
• Central Pneumatic; 1/2" Compact Air Twin Hammer Impact Wrench Assembly and Operating Instructions
• Agriculture; Air Impact Wrenches; 2007
• Ingersoll Rand; Air Hoses; Whip Hoses