Unscrew the studs from the engine block. How to remove a broken bolt are effective ways to remove them without damaging the threads. The best ways to remove bolts

Car owners often face a problem such as a broken bolt. And it makes no difference whether this car is Russian or foreign. All machines are subject to stress and break down over time.

And when you start repairing your car, a new problem may appear - a broken bolt. And now it's bad luck, how to unscrew it and throw it out? After all, you need to unscrew the broken bolt as soon as possible and continue the repair.

Why does the bolt break?

The bolt breaks due to the fact that it is either rusted or stuck. The more years the car is, the more "bad" bolts and, the more difficult it will be to repair the car. Most often, old cars have rusty bolts due to the fact that they are often in contact with moisture.

Long use of the machine will wear out all parts and bolts. For example, the chassis of a car is constantly in contact with moisture. Therefore, do not be surprised that something rusted somewhere.

The best ways to remove bolts

In order to proceed to the very unscrewing of the bolts, it is necessary to complete the preparatory work before that, or rather, cleaning the place of work from all dirt and dust. And in this we will be helped by the irreplaceable "Vedashka" (WD-40), well, or you can use machine oil.

In case none of this is there - just hit the bolt with a hammer or heat it up. But be careful, you must not damage other items.

What if the bolt breaks above the threaded surface?

Let's consider several options for solving the problem:

You can try unscrewing the bolt with pliers if you manage to "rip" the thread of the bolt a little;

The next method involves using a hacksaw for metal, a grinder or a chisel. The principle of operation is as follows - make a transverse hole for a screwdriver, then use the screwdriver itself to unscrew the bolt.

The third option will be associated with the use of a welding machine. Adhere to the following instructions: take a similar bolt in size and weld it to the broken one. Use a wrench to loosen the bolt, but do not overwork. You can use glue instead of welding, but there is a chance that the job will not get done, so use welding for reliability.

Bolt breaks flush with or below the surface

If you do not know exactly how your bolt broke off, then look on the Internet for photos of broken bolts and determine which one is similar to yours. Consider solutions on how to properly unscrew a broken bolt:

Take a drill with a thin drill bit and drill two to three or more thin holes in the bolt body. This is done in order to combine them later. Insert a screwdriver into the hole and unscrew the fragment of the bolt.

The second method involves more drastic measures. You will need: a drill, a tap, experience and a lot of patience. Do the following: drill a hole in the center of the bolt itself. Then you need to carefully cut a left-hand thread in it.

The moment you screw a new bolt with a left-hand thread into the thread made, then as soon as you reach the end, the old bolt should begin to unscrew.

Bolt broke flush with the surface

Be careful, there is a chance of damaging the threads. Instructions for loosening the bolts without damaging the threads:

Drill a hole in the center (use a thin drill);
Replace the thin drill with a thick one and drill more;
When the base of the bolt is almost gone, and the walls become very thin, then try to break the remnants of the thread. Use a thin sharpened wire or tweezers for this.
If you have done everything correctly, then you will not have to cut new threads or "drive" the old one.
If you have an "extractor" with a left-hand thread, then you can use it. Unscrew the rest of the debris.

If you cannot unscrew the broken bolt in any way, and even no way helped, leave this problem. It is better to trust a person who has already faced such problems and knows from experience how and what to do.

Note!

In any case, do not complicate your work and do not act rashly, this will entail other problems. We hope this article was helpful to you.

Note!

Car repair is far from the easiest process, and it doesn't matter what brand the car is and what year it is manufactured. All machines are subjected to serious stress every day, which means that breakdowns are inevitable. Most of these malfunctions can be easily corrected by an ordinary motorist in a garage, working slowly and carefully. Carelessness in car repairs can often complicate matters.

It so happens that in the process of repair work, when tightening or unscrewing bolts and studs, the thread breaks. This is very frustrating, especially if there is no knowledge of how to unscrew a broken stud. This situation baffles any repair. Let's try to figure out how to get out of this unpleasant situation.

Often, fasteners break if the master is large in size and has great physical strength, and the hairpin is stuck or rusted to the thread. We are not talking about those machines that have just rolled off the conveyor belts. Very often, owners of old cars that were stored and operated carelessly face similar problems. And more specifically, most likely such a machine was stored in places with high levels of humidity. Undercarriage parts - studs are in almost constant contact with water.Therefore, there is nothing surprising in the fact that these elements rust. As a result, the owner wonders how to unscrew the broken stud from the hub.

However, fasteners do not twist and break not only due to moisture, but also due to high temperatures. For example, the exhaust manifold can be heated up to 400 degrees. As a result of exposure to high temperatures for a long time, the stud corrodes.

How do studs break?

These fasteners can break in different ways. The most unpleasant situation is when they are cut literally flush. Then the master has to think about how to unscrew the broken hairpin, because in this case it is impossible to do without the use of special tools and technologies.

It is much better if the part breaks already at the exit from the thread, when a small part of its "body" is visible and remains on the surface. In this case, if the bolt has already been torn off, it will turn out, and it can be acted on with pliers, screwdrivers and welding.

Effective Ways to Deal with Broken Bolts and Studs

Professional locksmiths know several effective methods on how to unscrew a broken hairpin. Before starting this business, you need to prepare. These works mean cleaning the surface from dirt and grease. It is recommended to pre-treat the threaded connection with WD-40 or ordinary machine oil. You can also alleviate the situation by hitting the wreck several times with a hammer. Often the problem is solved by heating - a hairpin or bolt, provided that it looks out of the hole, is heated with a soldering iron. Then it can be removed relatively easily.

How to unscrew a hairpin if it breaks above the thread

If in the process it was possible to disrupt the thread at least a little, that is, if the fastener began to turn out, you can try using pliers or pliers. A good and powerful one will also help in this difficult task. In the second option, either a grinder may be required. Sometimes a chisel will also work - the main thing is not to make excessive efforts. How to unscrew a broken wheel stud in this way? Make a transverse hole for a screwdriver and unscrew the pin with this tool.

If the screwdriver did not help, then you can use This operation is easy enough. A bolt is prepared, the head of which approximately corresponds to the diameter of the stud. Next, the bolt is welded to the debris sticking out of the hole. Then, with the help of a key and without any extra effort, they try to unscrew the ill-fated hairpin. Experienced auto mechanics say there are corrosive special adhesives that can be used for cold welding. But they are not always effective.

If the pin breaks below the surface or in the hole

In this situation, you will need a drill, a thin drill for it, as well as good tool skills. Before unscrewing the broken pin from the engine block, drill 2-3 or more thin holes in the body of the pin. Then these holes will have to connect into one single piece. They insert a screwdriver here and try to unscrew the fragments of the bolt.

Left-hand thread in the stud

The second method is more complicated. It is used when it is impossible to turn out a broken hairpin using any of the available methods. In this case, the measures taken will be even more drastic. This method will take an electric drill, a tap, and a lot of time. The first step is to drill a hole in the hairpin - right in the center. Then carefully cut the thread in the hole with a tap.

Let's note an important point: before unscrewing the broken hairpin from the head, make sure that the thread is exactly "left". When a new bolt is screwed into the just cut part, the thread of which is the same, then at the moment when it reaches the end, the broken pin will begin to turn out.

Drilling

And finally, the third and most radical way. It is used to remove broken bolts and pins from the hole. This is drilling. The method is very difficult. It is much more complicated than all of the above and is the most dangerous. There is a risk of damaging the threads in the bore of the engine block or cylinder head. You should hold the drill securely, as if this is then there is a serious risk of damaging an expensive part. The stud is often made from harder grades of steel, and the head is made from aluminum. The collector body is cast iron, so it is also softer than a steel stud. The drill will definitely go from a hard stud to a softer metal. This happens especially often if the work is carried out in a confined space, and the drill is installed at a slight angle. The principle of drilling is as follows: you need to make a hole strictly in the center of the stud with a thin drill, after having screwed it, then install a thicker one in the drill and repeat the whole procedure.

The main thing here is drilling strictly in the center. When practically nothing remains of the body of the hairpin, the wall will become thin. It can be broken. You should very carefully break the rest of the stud using a pre-sharpened wire or tweezers. It must be remembered that any actions are carried out as slowly and accurately as possible. If you act in the heat of the moment, you will need to think not about how to unscrew the broken block pin, but also about how to restore the cylinder head itself. And these are significant costs.

We use a conductor

Drilling broken studs can be greatly simplified. This is true for those who often repair engines. The simplest conductor will help the master. Part dimensions are taken from real engines. On the conductor, which is a metal plate, the same holes are drilled in the same places as on the head, as well as on the manifold. Holes for bushings are also made in the jig. They will keep the part from moving on the block.

With the help of such devices, you can greatly facilitate the task and figure out how to unscrew a broken stud from the exhaust manifold by drilling without damaging the manifold itself.

Extractors

An extractor is a special device that allows you to remove the remnants of faulty fasteners or unscrew a broken stud. The device is very simple and ingenious at the same time. In order to remove a stuck or broken part, you need to hook it somehow, and then unscrew it. And all this is done very simply. It is required to drill a hole in the center of the stud, jam some tool in the shape of a cone or cylinder in it, then use this tool to unscrew the bolt. This is the extractor. These devices greatly facilitate the solution of issues such as unscrewing a broken pin from the manifold or from any other place.

There are several types of extractors:

Wedge-shaped.
Rod.
Spiral.
Screw.

Now these devices can be purchased in kits, but they are on sale and separately. Experts recommend using these tools. They make it much easier to deal with difficult situations such as broken bolts.

Choice of steel for the stud

If the studs will be purchased in stores, you should not choose the cheapest or those that you saw on the counter of the auto store. The most reliable products have a part number - 13517010. The penultimate figure indicates that this stud has sufficient tensile strength.

Before screwing in the stud ...

In order not to think about how to unscrew the broken pin later, before getting to work, it is recommended to lubricate the part with graphite, or better let the element unscrew together with the nut than break. Finally, the threads of the nut are also best treated with graphite grease. In the future, this will exclude breakage or breakage of the part.

In the process of repairing and maintaining a car, as well as any other equipment, there is often an urgent need to remove individual elements or chassis, body panels, etc. At the same time, the removal of the engine components and the suspension is often the most problematic operation. The reason is that the components can be tightened with bolts or studs, and the tightening torque is large enough.

If to this we add temperature differences in the engine compartment, oiling, accumulation of dust, dirt and other deposits, it becomes clear that unscrewing various bolts and other fasteners is not only a responsible and time-consuming, but also often difficult task. In this article, we'll talk about what to do if a stud or bolt is broken, and how to remove a broken bolt.

Read in this article

The thread of the bolt is torn off, the hairpin is broken, or the bolt in the engine block is broken: how to unscrew

So, bolts and studs often "sour", become covered with rust, can be overtightened or twisted skewed (not along the thread) during previous operations. This is true for all car models and brands without exception.

In any case, a common situation is when, while unscrewing the bolt, the master tore off the thread, broke the pin, broke off the head of the bolt, etc. A situation is also possible when the tightening torque is greatly exceeded when tightening, the bolt bursts, remaining under-tightened. Naturally, the rest of the bolt must be unscrewed, after which the pin or bolt must be replaced.

As a rule, bolts break when the bolt is rusted or stuck, and too much force is applied when loosening. This usually affects used cars or cars that are operated in difficult conditions. Threaded connections often start to create problems as a result of contact with moisture. Such contact is inevitable for the chassis of the car. In the case of the engine, the cylinder head is screwed to the cylinder block, the tightening torque is large.

One way or another, the most problematic situation is that the bolt can be flush broken, that is, it is not possible to unscrew it in the usual way or using simple tools. In other words, the "body" of the bolt does not protrude from the surface. In this case, there are several ways to solve the problem, with the most common being:

drilling a bolt;
unscrewing the bolt by welding;

First of all, the choice of this or that method depends on some conditions. If the bolt scrolled before breaking, then the main task is to "bind" to its body, in order to then unscrew the rest. If it is impossible to turn the bolt, then it is necessary to carefully ream the rest of the body in the hole. Let's take a closer look at the available methods.

To begin with, for a successful result, you need to know how to unscrew a torn bolt, as well as perform a number of additional work before unscrewing.

At the initial stage, it is necessary to remove dirt, oil residues, rust, etc. from the problem area. Also, it is imperative to apply a special agent to the threaded connection so that the bolts become "dehydrated". Special cleaners can be such a liquid. These are compounds that remove and soften rust, dirt, etc. WD-40 or pure oil is also quite suitable for these purposes.
Let's go further. If the debris protrudes above the threaded hole, several blows with a hammer can also be made on it, the bolt is additionally heated (for example, using a blowtorch). The only thing is that you can hit the bolt or heat it only if other parts, elements or the threaded hole itself will not suffer from such an impact.

If the thread was torn off (the bolt is spinning), then the broken bolt is unscrewed with pliers, an adjustable wrench, etc. You can also make a "groove" on the bolt body with a chisel, a hacksaw for metal or a grinder, after which you can try to unscrew the piece with a regular screwdriver.

Also in the wreck, if the body protrudes high enough, a through transverse hole is drilled into which a metal rod, nail, screwdriver, etc. is inserted. Then the resulting lever allows you to twist the piece with the help of improvised tools.

Often the body of the bolt does not protrude much above the surface, that is, the bolt is broken almost flush. This complicates the process of removing residues from the threaded hole. In this case, welding helps a lot. To implement the task, it is necessary to select a bolt with a head of a similar diameter, after which it is necessary to weld it with a welding machine to the body of the debris in the threaded hole.

Next, you can try to unscrew the chip with the key. It is important to remember that welding can be fragile at the joint, so you should not apply too much effort. We add that in addition to welding, sometimes special types of glue are used for such cases. At the same time, this method is not widespread, since these types of glue are far from always at hand, and also some doubts are caused by the reliability of fixation using such means.

The most difficult case is considered to be a broken bolt that breaks off, for example, flush with the surface or even below. Often this situation can be encountered when a bolt breaks off. In this case, the methods described above do not always work. To solve the problem, you need to know how to unscrew the debris from the hole, drill a bolt from the car engine block, etc.

First of all, you need to prepare a drill and a set with fine drills. Please note that it is not recommended to perform such work without certain skills. The main challenge is to drill a few small holes in the bolt body. This is done so that then it becomes possible to connect these small holes into one large one. Next, a screwdriver is inserted into the hole, after which the fragments are unscrewed.

A more difficult method is to cut a left-hand thread in the body of the broken bolt. In this case, you need a drill and a tap. First, a hole is drilled in the body of the debris, then a left-hand thread is cut with a tap. Then another bolt is screwed into this thread. After such a bolt is screwed in to the end, the debris should begin to unscrew from the hole.

The last available method of removing a bolt fragment that has broken in a threaded hole is drilling. The method is quite complicated and requires special skills. The main goal is not to damage the thread of the hole itself when drilling out the debris.

To drill a piece, first a hole is made in its center with a thin drill. Then the drill is changed to a thicker one, etc. After the body walls of the broken bolt are as thin as possible, try to break them with metal wire or tweezers. The debris is then removed from the hole. This method, if implemented correctly, eliminates the need to cut a new thread in the hole or restore an existing one.

Let's sum up

As you can see, there are several ways to unscrew a broken bolt or stud. In this case, in each case, it is necessary to separately take into account the nature of the breakage of the body, the very location of the fragment, the possibility of access to the problem area, the possible consequences of heating the remnants of the bolt, etc.

Finally, we note that before unscrewing the bolts, it is advisable to carry out processing before starting the procedure to remove dirt and soften rust. Moreover, if the various standard methods of unscrewing do not give the desired result (the bolt does not go), then it is optimal not to make great efforts so as not to break the stud.

The same can be said for tightening studs or bolts. The fact is that you need to tighten the fasteners with a strictly defined effort and in the specified order (for example, tightening the cylinder head). Ignoring this rule often leads to the fact that pins or bolts break, stretch, deform, etc.

In the event of such problems, it is better to contact experienced specialists who, in many cases, will unscrew the problematic torn off or sour bolt. If it is not possible to avoid breaking the bolt, then qualified craftsmen will remove the remnants from the hole with minimal risks, and, if necessary, restore the damaged thread.

How do studs break?

Effective Ways to Deal with Broken Bolts and Studs

How to unscrew a hairpin if it breaks above the thread

If in the process it was possible to disrupt the thread at least a little, that is, if the fastener began to turn out, you can try using pliers or pliers. A good and powerful adjustable wrench will also help in this difficult matter. In the second option, you may need a hacksaw for metal or a grinder. Sometimes a chisel will also work - the main thing is not to make excessive efforts. How to unscrew a broken wheel stud in this way? Make a transverse hole for a screwdriver and unscrew the pin with this tool.

If the screwdriver does not help, then you can use the welding machine. This operation is easy enough. A bolt is prepared, the head of which approximately corresponds to the diameter of the stud. Next, the bolt is welded to the debris sticking out of the hole. Then, with the help of a key and without any extra effort, they try to unscrew the ill-fated hairpin. Experienced auto mechanics say there are corrosive special adhesives that can be used for cold welding. But they are not always effective.

If the pin breaks below the surface or in the hole

Left-hand thread in the stud

Drilling

And finally, the third and most radical way. It is used to remove broken bolts and pins from the hole. This is drilling. The method is very difficult. It is much more complicated than all of the above and is the most dangerous. There is a risk of damaging the threads in the bore of the engine block or cylinder head. You must hold the drill securely, as if it is a cylinder block, then there is a serious risk of damaging an expensive part. The stud is often made from harder grades of steel, and the head is made from aluminum. The collector body is cast iron, so it is also softer than a steel stud. The drill will definitely go from a hard stud to a softer metal. This happens especially often if the work is carried out in a confined space, and the drill is installed at a slight angle. The principle of drilling is as follows: you need to make a hole strictly in the center of the stud with a thin drill, after having screwed it, then install a thicker one in the drill and repeat the whole procedure.

We use a conductor

With the help of such devices, you can greatly facilitate the task and figure out how to unscrew a broken stud from the exhaust manifold by drilling without damaging the manifold itself.

Extractors

There are several types of extractors:

Wedge-shaped.
Rod.
Spiral.
Screw.

Now these devices can be purchased in kits, but they are on sale and separately. Experts recommend using these tools. They make it much easier to deal with difficult situations such as broken bolts.

Choice of steel for the stud

Often auto mechanics make studs themselves. They recommend making these fasteners from the following steel grades: 35, 40, 45, 50, 55, 60. If you make a new fastener from this metal, the result will be a product with sufficient tensile strength.
If the studs will be purchased in stores, you should not choose the cheapest or those that you saw on the counter of the auto store. The most reliable products have a part number of 13517010. The penultimate number indicates that this stud has sufficient tensile strength.

Before screwing in the stud ...

In order not to think about how to unscrew the broken pin later, before getting to work, it is recommended to lubricate the part with graphite, or better with copper, grease. Better to let the element unscrew together with the nut than break. Finally, the threads of the nut are also best treated with graphite grease. In the future, this will exclude breakage or breakage of the part.

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How to unscrew a broken hairpin

You will need

- file;
- screw;
- drill;
- screwdriver;
- wrench;
- gimbals or trox;
- lighter.

Instructions

If the cap of the bolt breaks off, but at least some part of it remains, try to make a groove in it for a screwdriver with a file. Then carefully unscrew the damaged bolt with a suitable screwdriver.

When the cap is completely broken off, you can use professional tools to unscrew such bolts. Purchase special gimbals from an auto parts store. Drill a hole in the bolt corresponding to the size of such a gimbal and screw it in there. Then remove the bolt from the protruding end of the gimbal.

You can pull out the bolt in another way. Drill a hole in it so that only 1-1.5 mm is left to the thread. During drilling, periodically dip the heated drill bit in machine oil. Then carefully pry off the rest of the bolt with any sharp metal object, such as the same screwdriver. The main thing is to correctly calculate the size of the drill so as not to touch the thread. This option is also suitable when you need to get a split bolt.

If the cap of the bolt is torn off but a threaded debris is sticking out, use the nut to remove it. To do this, select the size of the nut and heat it strongly over the fire. You need to hold it with tweezers or forceps with refractory handles so as not to burn your hands.

After the nut is hot enough, screw it onto the protruding piece of the bolt. Due to the high temperature, the nut must be welded to it. After some time required for the metal to cool down, take a suitable sized wrench and unscrew the bolt by the nut welded to it.

You can also try to pull out the bolt with an asterisk wrench or, as it is also called, a trox. To do this, you need to drill a hole in the bolt and drive trox into it. When it comes to its full length, unscrew the bolt for it.

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Unscrewing a broken bolt or stud from the cylinder block and other elements: solving the problem

In the process of repairing and maintaining a car, as well as any other equipment, there is often an urgent need to remove individual elements of the internal combustion engine or chassis, body panels, etc. At the same time, the removal of engine components, attachments and suspension is often the most problematic operation. The reason is that the components can be tightened with bolts or studs, and the tightening torque is large enough.

The thread of the bolt is torn off, the hairpin is broken, or the bolt in the engine block is broken: how to unscrew

drilling a bolt;
unscrewing the bolt by welding;

To begin with, for a successful result, you need to know how to unscrew a torn bolt, as well as perform a number of additional work before unscrewing.

At the initial stage, it is necessary to remove dirt, oil residues, rust, etc. from the problem area. Also, it is imperative to apply a special agent to the threaded connection so that the bolts become "dehydrated". Special cleaners can be such a liquid. These are compounds that remove and soften rust, dirt, etc. WD-40 or pure oil is also quite suitable for these purposes.
Let's go further. If the debris protrudes above the threaded hole, several blows with a hammer can also be made on it, the bolt is additionally heated (for example, using a blowtorch). The only thing is that you can hit the bolt or heat it only if other parts, elements or the threaded hole itself will not suffer from such an impact.

Often the body of the bolt does not protrude much above the surface, that is, the bolt is broken almost flush. This complicates the process of removing residues from the threaded hole. In this case, welding helps a lot. To implement the task, it is necessary to select a bolt with a head of a similar diameter, after which it is necessary to weld it with a welding machine to the body of the debris in the threaded hole.

The most difficult case is considered to be a broken bolt that breaks off, for example, flush with the surface or even below. Often this situation can be encountered when a bolt in the engine block breaks off. In this case, the methods described above do not always work. To solve the problem, you need to know how to unscrew the debris from the hole, drill a bolt from the car engine block, etc.

Let's sum up

krutimotor.ru

Tool for drilling broken pins.

Most drivers who repair their cars on their own are faced with the need to drill out a broken stud, such as an exhaust manifold. After all, the exhaust manifold mounting studs break easily, since they work in difficult conditions - the exhaust manifold temperature reaches 400 degrees. And from constant heating and cooling, the stud material corrodes, and the corrosion products work no worse than good glue, tightly gripping the threaded connection of the nut and stud. In addition, the metal of the stud becomes brittle and often breaks off. This article will describe how to drill a broken-off pin, and how to make a simple device to facilitate drilling in a hard-to-reach place - a simple jig.

An experienced car owner always tries to prevent the process of souring nuts and studs, for example by ordering taller stainless steel or brass nuts that cover all the threads on the stud. And some screw cap nuts, which are already on sale now. In addition, the threads are lubricated with graphite grease, which reduces the risk of sticking and sticking of the fastener threads.

And before unscrewing the nut, it is recommended to moisten the threaded connection with a penetrating liquid, for example, the common "Vedashka" (WD 40), possibly brake fluid, kerosene, diesel fuel, or at least vinegar. If this does not help to unscrew the stuck nut, then it is advisable to heat it with a small gas burner, or at least with a hot air gun.

But all the same, the heating temperature of the collector and the exhaust pipe does its job, and the metal of the stud, during prolonged operation in conditions of high temperature and vibrations, changes its properties, and not for the better. Microcracks appear in the body of the hairpin, and as a result, without even pressing the wrench hard, the nut does not even think to turn away, and the hairpin is easily “cut off”.

When even one, well, or several of the exhaust manifold studs are broken off, the leakage of the joint between the manifold and the head, or the joint between the manifold and the exhaust pipe, is accompanied not only by loud exhaust, but also by an unpleasant smell, and can even lead to a fire. And as a rule, replacing the gaskets with new ones will not help; you need to carefully drill out the broken-off pin, “drive out” the thread with a tap, and screw in a new pin.

In practice, this is not as easy to do as in words, especially in an inconvenient (hard-to-reach) place when the motor is on the car. Naturally, when the engine is removed for repair, everything is much easier, but more often you have to wield a drill in a very uncomfortable position under the hood (when the engine is in place).

Before drilling out the broken-off pin, you should try to attach a suitable nut to the remainder of the pin, and try to weld this nut to the body of the broken-off pin. It is naturally more convenient to cook with a semiautomatic device, and not with an electrode. And the risk of sticking the body of the pin to the aluminum body of the head or to the cast-iron body of the collector (there are also cast-iron heads) is minimal, since aluminum or cast iron is not welded with a steel wire of a semiautomatic device in this case. After welding the nut, it is unscrewed with a wrench together with the stud, and this is often possible, since the heated stud usually turns off and unscrews.

But it happens that it is very inconvenient (little space) to make a high-quality tack weld, then you can try another method, using a special tool - a set of gimbals, as in the photo on the left. Such kits are already easy to find on the market. From the set, a gimlet suitable for the diameter is selected, a hole is drilled in the hairpin, for the gimlet to enter and it is screwed into the stud hole.

Its thread is left, that is, it must be twisted counterclockwise, and the hairpin is also unscrewed to the left. When deepening, the cone of the gimlet deepens and a moment comes when the drilled hole does not allow to deepen further. At this moment, a piece of the hairpin begins to unscrew.

However, even this tool often fails to unscrew the fragment of the collector pin. Since the temperature and corrosion have done their job and the piece of the hairpin literally grows together with the body of the head or bottom of the collector. And the metal of the gimbal is hard, but brittle enough, and it can break. This leads to even greater problems, since it is not possible to drill out the hard steel of the gimbal fragment with a conventional drill. In this case, the winning drill helped me, but there was a lot of fuss.

Since when drilling a piece of a gimlet, the drill will definitely go away from the center. Whatever this happens, you need to use the conductor, which is described below.

The most reliable way is to drill out the rest of the stud, and then drive the thread with a tap. It is very important that the drill does not go to the side during drilling, because the stud is made of harder steel, and the head body is made of softer aluminum (the cast iron collector body is also softer than the steel stud, if you drill a broken hairpin at the junction of the collector bottom and outlet pipes).

And the drill always leads away from the stud into a softer metal, especially if you drill in a confined space and drill at a slight angle. Naturally, you need to try to keep the drill strictly perpendicular to the plane being drilled. There are masters with a good eye and normally doing this kind of work without any tools.

To do this, first the center of the pin is located, it is well pored with a core, and then first a guide hole is drilled with a small drill of 3 - 4 mm for a thicker five millimeter drill, and then a 6.5 mm drill is used. Drilling with a drill of this diameter is sufficient for further removal with an awl, or a sharpened screwdriver, of the remainder of the 8 mm stud. Or simply the thread is driven with an M8 tap and the rest of the stud turns into shavings.

A device installed on the pins for precise drilling of a piece of a pin. 1 - base plate, 2 - conductor fastening nut, 3 - long sleeve for a drill, 4 - a full standard stud, 5 - short sleeve for studs.

But to simplify the operation of accurately drilling broken pins, especially for those craftsmen who are constantly engaged in repairs, a simple device (conductor), for example, such as in the figure on the left, will help. The dimensions of this jig, shown in the drawings below, are calculated for accurate drilling of the studs that connect the lower part of the Zhiguli manifold to the exhaust pipe.

But a similar jig can be made for drilling the pins that connect the manifold to the engine head, and for any machine. You just need to accurately measure the distance between the studs of your particular engine, and then drill holes for bushings 3 and 5 at the same distance.

You don't even have to measure the distance between the pins with a measuring tool, but simply attach a sheet of cardboard to the pins and gently tap the cardboard on the pins with a hammer. An accurate cast of the location of your particular studs will be provided.

Then, having cut out the holes for the studs in the cardboard template, put the template on the studs, and tap with a hammer in the area of the stud fragment and thus determine the place for the long sleeve 3. And according to this cardboard template, plate 1 (base) is cut out of sheet steel, 12 mm thick , in which holes are drilled for bushings 3 and 5 (according to the template).

Guide bushings are inserted into the holes of the plate, which are turned on a lathe according to the drawing on the left. Moreover, short bushings 5, with an inner hole diameter of 8.1 mm, are intended for non-broken pins, and a longer bushing 3 (with an inner diameter of 6.5 mm) is inserted into the plate where the broken-off pin is. And if the broken hairpin protrudes strongly outward, then its protruding part must be grinded off.

By the way, having ordered four short bushings 5 and one long bushing 3 to the turner, you can later use them for other plates (devices of a different shape), since the bushings are easily removed from one plate and rearranged onto another.

The plate (base) is pressed against the plane of the manifold (or the plane of the engine head, if the plate will be made for drilling the head studs) using high nuts 2.

All parts except bushing 3 can be made from any steel you find. But the sleeve 3, in which the drill will work, and which does not allow the drill to go to the side, should be carved from strong alloy steel (at least St 45, 50) and hardened. Otherwise, a sleeve made of ordinary steel will not last for a long time and its inner hole will quickly wear out.

When grinding a new hairpin instead of a broken one, you should know that it is undesirable to grind it out of any available steel. For example, the most affordable steel St.3 has a tensile strength of 39 - 49 kgf / mm², and this strength is not enough for the manufacture of exhaust manifold studs. More durable steel grades St.35, 40, 45, 50, 55, 60 (according to GOST 1050 - 88) are suitable for studs.

Having made a new hairpin from one of the steels listed above, its tensile strength will be sufficient, in the range from 50 to 80 kgf / mm². If you buy, and not order the turner new factory studs, then do not take the first ones on the counter, but only those that have normal packaging with the part number - 13517010. The penultimate digit 1 in this number indicates the breaking strength of the stud within 50 - 80 kgf / mm².

When screwing a new stud into the head or collector body, lubricate its threads with graphite or copper grease, even if it is better later, when you try to unscrew the nut, the stud will be unscrewed together with the nut, which will break off. Well, before screwing the nut onto the stud, of course, we also lubricate the thread of the nut with "graphite".

Having made such a device for drilling broken off collector pins and not only for it, you will greatly simplify and speed up the operation to remove the stud fragment (especially if you are doing repairs professionally), and the risk of damage to the head body or collector during drilling will be reduced to zero, success to everyone.

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Personally, I have repeatedly encountered the problem when a bolt or hairpin breaks at the root. Moreover, I am not some kind of auto mechanic or locksmith. I say all this to the fact that this happens quite well with an ordinary person who periodically deals with technology or other technical part.
Well, since you are in such a situation, then you should not despair - everything is fixable. I offer you seven ways to get out of this situation and free the thread from the debris of the stud or bolt.

Preparation before turning out the wreck

But do not rush to immediately start unscrewing. Before doing this, you need to take steps that will ease your efforts.
First of all, sprinkle the breakage with penetrating lubricant. It can be any liquid key, WD-40. Let's wait a bit.

Further, in order to slightly remove internal stresses, we will thoroughly warm up the fragment and the place around with a gas burner.

Well, then let's go directly to unscrewing a fragment of a stud or bolt.

Method one: flat screwdriver and hammer

This is the easiest way, but it doesn't always work. In about half of the cases, the hairpin breaks off with a protruding splinter, which you can just catch on to.

We take a flat screwdriver, push it against the shard and with shock movements at an angle towards unscrewing the thread, carefully turn the fragment.

This method is suitable if a lot of effort is not required to unscrew. If the effort is not enough, then we move on to the second method.

Method two: we try to unscrew with a chisel

This method is similar to the first one, only we take a chisel instead of a screwdriver. In the same way, we rest against the splinter and we twist it with percussion movements.

The chisel makes it possible to create more force than a screwdriver.

Method three: core and hammer

If the bolt fragment does not have splinters, or even breaks off just below the final surface of the thread, then you can try using a core.

We push the core against the surface of the fragment with displacement and blows at an angle, we twist it until the fragment can not be hooked with pliers or another tool.

The fourth way: we weld the nut by welding

In my opinion, this is the most effective and fastest option, but if you have a welding machine. Its essence is to weld a nut on top of a bolt fragment.
So, to do this, we take a nut, but not the same size, but a couple of units larger. That is, if the broken bolt was at 10, then we take the nut at 12. This is necessary for a better and larger welding place.

Holding the nut with pliers, we put it on the piece, but not in the center, but with an offset. With an electrode we weld a stud with a nut to one side inside the nut.
Then, after cooling down, unscrew it with an ordinary wrench.

Fifth method: unscrew the hairpin with an extractor

Here you will also need a specialized tool specially designed for unscrewing broken pins and bolts - an extractor.

We punch the center of the stud so that the drill does not run around when starting drilling.

We drill a hole of the appropriate diameter for the extractor.

We insert the extractor into the hole and unscrew it with a key.

Sixth way: we drill out a piece

The method consists in picking up the drill according to the lower thread diameter of the stud and drilling it out. A very difficult way, it requires skill.
First, we go through the drill with a smaller diameter.

Then we drill as close as possible.

We knock out the fragments and remnants of the stud with a flat screwdriver.

This method of removal does not always justify the effort, but it deserves your attention.

Seventh method: we drill under a clean one and make an insert

The most time consuming and costly method of all. But there are times when this is the only working option to return the node to a working state.
We drill the pin clean together with the thread.

We cut a new thread with a tap.

This can be done if the design allows you to pick up a now thicker bolt or stud. If not, we buy an insert or order from a familiar locksmith.
Lubricate the external thread with a thread lock and screw it in.

Sewing flush.
What method did you use? Write in the comments, I think your experience will be interesting! All the best!

The node has been restored.