Impact Wrench Repair: How to Repair a Broken Impact Wrench Motor

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  • 2-3 hours
  • Intermediate
  • 10-25
What You'll Need
Lubricating oil
Piece of clean, soft cloth
Dowel, measuring 1/2 " diameter

Impact wrench repair requires a little bit of knowledge and some basic tools. An impact wrench is an important power tool and is known by several names, such as an air wrench, rattle gun, air gun and torque gun. This is a socket wrench that delivers an output which is of high torque. The impact wrench requires minimum exertion by the user and has a rotating output shaft. The most common power source of an impact wrench is compressed air, and both hydraulic and electric power is used to operate the wrench. This is one of the cordless devices that have become very popular and almost a necessity in the modern day toolbox. The impact wrench is used in most modern industries, especially in the ones where there is a heavy load of automotive repair, maintenance of heavy equipment, and product assembly. An impact wrench is also used in major construction projects; it can also be used in situations where output is required at a high torque. There could be many reasons why the impact wrench motor may not be functioning. Here’s how you can troubleshoot a broken impact wrench motor.

Step 1 – Inspection and Disassembly of the Motor

An impact wrench is a compact instrument, and there are chances that the motor may not be assembled correctly, and for this reason, it may be giving you trouble. To check for the proper assembly of the motor, it has to be disassembled. From the front of the motor, lift the rear hammer washer and remove the two motor washers. The motor is assembled in a small area, also known as the motor housing. Once the washers have been removed, you can remove the motor by simply grasping the splined end of the rotor and removing it.

Step 2 – Cleaning and Lubrication of Motor

The impact mechanism inside the hammer case may need to be cleaned and lubricated. Use a clean cloth to remove the dirt and grime caught on the grease. Using a machine lubricant, soak a small piece of cloth and apply it on the smaller parts of the impact mechanism.

Step 3 – Assembly of Motor

Place the reverse valve bushing seals properly into the undercuts on the valve bushing. The reverse valve should be dampened with light lubricating oil to make sure that it continues to move. Install the detent spring of the reverse valve in its proper hole. Move the wrench so that you are facing the handle and the wrench is in upright position. To make sure that the reverse valve is moving, rotate it in the left to right motion in the reverse wall bushing of the splined end.

The reverse valve knob can be now attached to the knob screw. Use a screw driver to tighten the screw to a torque of 60 to 70 inch-pounds. If the throttle value seat has been misplaced, install a new one by pushing it into place using a dowel measuring ½” diameter. Insert the trigger assembly back into the trigger bushing.