How to: Bolt Extraction from a Cylinder Head using a MIG Welder

If you have worked on an older car, then you know how frustrating it can be when you find a broken bolt. Of course, you can always drill it out, but you risk causing damage to the threads, so here is an easier solution that we find works almost every time.

In this video, J-Tech Automotive and Diesel instructor Robert Vachunek will show you how to use a common MIG Welder in order to remove a a broken bolt from a Cylinder Head.

What you will need:

  • MIG Welder
  • A nut larger than the stud
  • A washer
  • Protective welding gear
  • Wrench

Before Robert preps the engine block and gets it ready to build, he is going to remove the broken bolt. First thing is to grind the bolt smooth, after that is complete take a flat washer and weld it over the top of the stud. Once this task is achieved you will then weld a nut over the flat washer that will allow you to put a wrench or a socket on top of it and screw it right out. Seems easy enough, now let’s get started.

As always when it comes to working this machinery, safety comes first. With his safety glasses in place and the proper gloves, Robert begins grinding down the stud so it is flat and smooth for the flat washer to be welded over top of it.  Be sure you have a nice clean surface because when you go to weld the washer onto the head of the bolt any rust or oxidation will cause the weld to pop and you will not have a good clean weld. This is important because if you do not have a clean weld then the chances are high that the washer and nut will spin right off of the bolt and the bolt will not come out of the engine block.

Next, Robert prepares to weld the washer to the bolt by applying the proper welding gloves and mask before beginning. When all of your proper gear is on, place the washer on top of the bolt. (Here is a helpful tip: to hold the washer in place while you are welding use a long neck screw driver.) Once the washer has been welded to the bolt place the nut on top of the washer and tack it on the sides. Now begin to fill the center, pay close attention because you want to be sure there is a strong weld in the center.

It is time to pull the bolt out! Do not wait until it cools down to remove the bolt because waiting for it to cool could cause the properties of that steel to change and the bolt will then get locked into the hole.

Place the wrench over the bolt and begin to turn the bolt counterclockwise to remove it from the engine block. After the bolt has been removed take a look at the threads inside and be sure they are nice and clean.

The blending of innovative tools, high-tech instruments, and logical thinking has taken the world of automotive repair to a new level. While the technology is impressive and beneficial, it’s no substitute for skilled technicians.

If you’re drawn to critical thinking, problem-solving, and innovation, a career in the automotive industry might be for you. Whether you’re drawn to Automotive Technology, Diesel Technology or the combination of operating and maintaining a rig through Commercial Truck Driving, we have the programs to help kick-start your career. Call (877) 447-0442 today for more information.

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