A hammer drill is a construction tool that is used to perform slotting and drilling operations. Thanks to a special mechanism, the hammer drill very efficiently and quickly makes a hole in various materials. It can be used in working with concrete, brick, metal, wood, stone. Bosch brand hammer drills are very common among builders and ordinary people, so it is very important to know how to repair these devices if they break down.
Important pay attention to the original models! There is a fake Bosch Hammer Drill 32. Beware of fakes!
There are two types of hammer drills:
Electrical and mechanical parts are the main components of this tool.
The electrical part consists of:
The composition of the mechanical part is as follows:
This device can be supplied with various accessories in the form of a drill, crowns, a vacuum cleaner and other parts.
To repair a rotary hammer, you first need to disassemble it correctly. And we start doing this by disassembling the cartridge.
Important! When disassembling, be extremely careful about where and when you remove certain parts. Fold them so that you never lose them. This determines whether you put the tool back or not.
If any parts in the tool are damaged, broken, or do not perform their function well, then they simply need to be replaced. If the brushes are worn out, then during disassembly they are simply replaced with new ones. The hammer drill cartridge when the rim rotates slowly, a worn boot, and failed bearings are also replaced. But there are other problems that you can fix. If a breakdown of the winding occurs, then the stator and armature must be rewinded. You need to monitor the lubrication and lubricate some parts from time to time.
Before you fix anything in this model, you need to familiarize yourself with the features of the device, the circuit and the principle of operation. The rotor shaft transmits rotation to the barrel shaft through an intermediate shaft, the bearing of which directs the return movement to the impact piston.
When disassembling the barrel shaft in the impact block, you need to pay special attention to fixing the spur gear. Before removing it, you need to remove the 3 pins that secure it in this model.
In this bosch gbh 2 24 dsr hammer drill, the intermediate shaft consists of a switching part, a bearing assembly and a clutch. The latter deteriorates most often because its teeth wear out quickly. Repairing this damage consists of correcting the profile of the engagement teeth. You can often notice that there is no impact. The hammer drill may gradually stop chiseling due to wear of the rubber parts, which need to be replaced in time. And if you apply more force than necessary, this can lead to the firing pin jamming in the impact piston.
In this model of tool, the splines sometimes wear out. In this case, it is necessary to disassemble the gearbox (it is almost similar to the Bosch 2-24, only the bearing is different). It is better to replace the entire barrel, because along with the splines, the firing pins also wear out.
As you can see, you can repair rotary hammers at home with your own hands. At the same time, do not spend large sums on various types of repairs in service centers, which, as we know, are very expensive. But do not forget that you must adhere to the rules of use and safety precautions.
First, inspect the rotary hammer with the intention of identifying visual defects. The weak point of the hammer drill is the plastic boot on the chuck: it often breaks, causing loss of stoppers. To prevent this problem from occurring, it is recommended to use a long drill bit.
The hammer drill begins to be disassembled from the top unit. First remove the rubber tip, then the lock washer, and then the head and spring. Just after this, pull out the ball.
Our client just needs to carefully fold the removed parts (nothing should get lost, because later it will be impossible). Later, remove the body of the power tool from the gearbox: a crack (3-5 centimeters) should appear between the body of the hammer drill and the gearbox.
Remove the switch by switching it to the hammer and drill position. Then remove the housing from the gearbox.
A power tool can stop working for a variety of reasons. For example, the armature or stator is covered. To fix this problem, unplug the hammer drill from the power supply, unscrew the three bolts on its back cover, and then remove the cover. Check the condition of the brushes, then just ring the cable and the power button.
If a breakdown is detected, inspect the cable in order to identify the causes of a strong bend. If no visible cause of damage to the cord is found, unwind the cable without looking through each strand of the cable. Pull out the damaged core, clean the part where the breakdown occurred, then ring the cable to check its integrity and do not assemble the hammer drill.
Sign the removed parts, because otherwise it will be difficult to assemble the hammer drill correctly.
Check the condition of the brushes frequently, as replacing brushes is much cheaper than replacing an armature. Every time you replace brushes, lubricate the rear bearing (this will prevent overheating of the hammer and its premature failure).
How to disassemble a Bosch rotary hammer
What for an ideal attic
Tips for arranging an attic
To make the attic light, in addition to the windows in the gables, use dormer windows in the roof slope. Quantity and size are calculated according to the 10:1 rule.
Decide on the location of the handle at the top, as it is also called at the bottom, based on the installation height of the window. For children's rooms, choose windows with safety glass.
Professional installation using branded installation kits for hydro-thermal insulation doubles the warranty period - up to ten years.
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expensive, gets hot, poor vibration protection
a completely incomprehensible device. Blue Bosch, professional hammer drill. But you can’t work with it for long. It gets hot, it needs to cool down. After a couple of hours of work, the hands simply fall off from the vibration. Home – powerful, not convenient, but prohibitively expensive for a home instrument. Moreover, it is expensive: the device itself, branded equipment (one drill can cost fifty times more than on the financial market), repair. Replacing the cartridge, which I had to do at my own expense, cost a third of the price hammer drill. According to the act, the cartridge itself turned out to be much more expensive than in the store. After the repair, I realized that what I spent on the hammer drill was more than what it cost. When it breaks, I’ll just buy another one, especially since super-expensive drills promise to last a long time.
convenient, thoughtful, powerful
high vibration, absolutely impossible to repair - expensive, gets hot
My opinion is this: the perf is good, but not for. Even despite the fact that it is blue. For housework. and sell. However, excuse me, active use of a hammer drill in the workplace involves heavy loads. Not, by and large, the price tag for this common rumor is that Bosch directly hints at such a situation in any way: don’t spare the money, it works for us. However, it doesn't work! More precisely how - it should not work powerfully for a long time. Logical? And what happens to this perf? The first question is what strong vibration. Okay, this is a hammer drill, although in any case it is very strong when compared with similar competitors. Further. The hammer drill gets very hot. No, and again, this is not exactly a problem, but it speaks volumes about the quality. A year later the trunk was damaged. Karl, that's how it is. Professional Bosch. Repair, it is, by and large, not expensive. Alas, after a year? The repaired barrel will last a lot. We didn't have to find out. They had just decided on the barrel, when the perf produced a sheaf of sparks, the smoke did not stink: the anchor was covered. Ultimately, what's the point in renovating? For that kind of money, I’d rather buy two with a less sonorous name, it’s twice as profitable.
High cost, expensive spare parts, empty equipment.
It copes with the main task - drilling concrete floors. It's a pity that for such a price there is not a single drill included. But, to be honest, this is my fault, only when I brought it home after the purchase did I realize that all the available drills were round - for a three-jaw chuck. I had to postpone the tests for a day. A set of bits, drills and heads from Bosch costs the same as a separate cheap hammer drill. At the very beginning the cord was damaged and had to be replaced. I didn’t even think about future problems. When, at the very end of the one-year warranty, the engine burned out (either I overloaded it, or something jammed inside, but it stood up and smoked), the service denied the warranty precisely because of the cord (it wasn’t even discussed). We soldered the repairs on a general basis. Replacing the engine, cleaning and lubrication will cost me more than half a new hammer drill. And they can add something else to the bill.
Durable material and good quality
I bought the drill a month ago and have not yet been disappointed. I bought it because of good reviews about the company. As for the hammer drill. Powerful and reliable. I just don’t like that it gets too hot
Bosch hammer drills are used for laying electrical wiring, destroying partitions and drilling holes in hard materials. They will replace an electric drill and... Depending on the power, the tool is suitable for domestic and professional needs.
A hammer drill is a multifunctional construction tool.
The device consists of an electric motor and gearbox, and a cartridge for attachments. The handles and control system are located outside.
In appearance, there are straight and L-shaped models. The advantage of the latter is better ventilation of the engine located vertically. That is, such a device can withstand a larger volume of work. The downside is the greater weight of the tool.
As a standard, the hammer drill has three operating modes:
Bosch rotary hammers are equipped with SDS chucks and require the use of special shank attachments. The most common standards are SDS plus and SDS-max.
The devices have increased productivity. An example is the Bosch GBH 7-46 DE model.
Some devices are equipped with an overheat protection function. It allows you to extend their service life.
If so, give preference to a hammer drill with three modes. Additionally, purchase crowns and drills, peaks and blades, as well as special lubricant.
The Bosch GBH 2-26 DRE rotary hammer belongs to the class of professional tools. And suitable for daily use. It is characterized by light weight and high performance.
Technical characteristics of Bosch GBH 2-26 DRE:
The Bosch GBH 2-26 DRE rotary hammer comes with an additional handle, a depth stop of two hundred ten mm and a tool case.
The model has a number of features:
1. Safety precautions:
2. Working with the device:
Professional construction tools always work under extreme conditions, which is why both the mechanical and electronic parts of the hammer drill have an increased working life. Based on practice, tools from brands such as Makita, Bosch or Interskol occasionally burn out during the warranty period, but at some point everything breaks. One of the most vulnerable places of any hammer drill is the power button with [...]
The procedure for disassembling Interskol rotary hammers In recent years, Interskol rotary hammers have become especially popular. They are reliable in operation and easy to repair. It's easy to get spare parts there. Interskol rotary hammers have a wide selection. The tools are conditionally divided into two sectors: hammer drills equipped with an SDS-plus type chuck, and non- hammer drills with an SDS-max type chuck. Repair of the Interskol rotary hammer can be carried out both in service centers, [...]
Grinder repair. We remove the backlash. Repair, Angle-grinders. Read also Grinding Concrete Floors with a Grinder Do-It-Yourself... Grinding a Concrete Floor The rapid development of chains of hypermarkets, hotels, restaurants, salons, office and shopping centers, exhibition halls creates a demand for strong, abrasion-resistant, dust-free and non-marking beautiful floor coverings. The simplest covering is a polished concrete floor. Only high-quality surface treatment [...]
A rotary hammer, like any electric tool, requires careful treatment, proper operation and timely preventive maintenance. If these standards are neglected, the device may fail without exhausting its service life. In case of some malfunctions, you can repair a hammer drill yourself, but to eliminate breakdowns associated with the electrical part of the engine, you will need the help of a specialist.
All unit malfunctions can be divided into 2 groups: mechanical and electrical.
If any mechanical malfunction appears in the hammer drill, then its presence can be determine by ear(noise increases, grinding noise appears).
You may also experience increased vibration or an unpleasant odor emanating from the unit body.
So, mechanical failures include the following:
Malfunctions associated with the electrical part of the hammer drill may also be accompanied by an unpleasant odor from the device body and sparking. Also you may notice that The engine heats up quickly and hums without rotating, or smoke appears from it.
Electrical failures of the device include the following:
To eliminate mechanical and electrical faults (with the exception of a broken electrical plug), disassembling the unit body is indispensable. The most popular brands among craftsmen, both home and professional, are Bosch, Makita, Interskol, and Energomash hammer drills. The design of units from different manufacturers is approximately the same, therefore the methods for disassembling the devices will be similar. But you should not disassemble the device completely, since it will be difficult to put it back together. The photo below shows what a completely disassembled hammer drill looks like.
Disassembling the unit for troubleshooting should be carried out carefully, inspecting each removed part. To make assembly easier, it is better to photograph the disassembly process. If you do not find any external defects on the device, then it is recommended to start disassembling it with the cartridge.
If disassembling the unit housing is required, you must first remove the operating mode switch.
To get to the electrical part of the device, if you suspect that this is where a breakdown may occur, you must perform the following steps.
If you need to disassemble a barrel perforator with a vertical electric drive, first remove the handle, and then unscrew the bolts holding the motor.
The main sign that it is time to change the brushes is the formation of increased sparking in the area of the electric motor commutator, rapid heating of the brush holders, and a burning smell. When the brushes are not worn out, the spark can only be seen under them. Otherwise, the spark is visible throughout the entire circle of the collector.
The presence of a spark around the commutator circle with unworn brushes is a sign of bearing wear, rotor or stator insulation failure, commutator plate burnout, stator or rotor burnout.
Another sign that the stator has burned out is the presence of sparks under only one electrode. If you have a tester, then you can use it check stator and rotor: measure the resistance on the rotor and stator alternately. If it is the same on both windings, then everything is fine with the stator. If you notice clear signs of problems with the rotor or stator in your hammer drill, you will have to take the device to a service center for repair. As for the brushes, you can change them yourself.
To get to the place where the brushes are installed, you will need to disassemble the housing in which the motor is installed, or simply remove the back cover. Opening the lid, you will see brushes secured in special holders. The photo below shows what these parts look like.
Brushes that are installed on rotary hammer motors come in 3 types.
It is very important not to wait until the engine sparks and then change the brushes. Replacement is needed after they are worn to 1/3 of the nominal value (8 mm). Even if one brush is worn less than the other, both still need to be replaced.
Pay attention to the condition of the spring in new brushes and the fastening of the contact. If the spring falls off while the engine is running, it will suffer significant damage. Also, if the spring is weak, then it will not be able to provide good contact.
Be sure to check thoroughly before changing brushes clean the rotor and stator from residual graphite or coal dust. These parts can be cleaned using technical or medical alcohol.
Next, you should secure the electrodes in the holders and rub them into the collector. To do this, place a piece of fine-grain sandpaper on the commutator and use rotational movements in different directions to grinding in the electrode. The grinding continues until the contact area of the electrode is slightly rounded. This will ensure a better fit to the collector plates and, accordingly, better contact.
The impact mechanisms of rotary hammers differ in their design, depending on which family the devices belong to. Therefore, the repair of these mechanisms will take place according to different principles.
Rotary hammers with a vertical engine usually have an impact unit based on a crank mechanism (CSM). Below is a diagram of this type of impact mechanism.
The following photo shows a section of the device, where you can see the location of the crankshaft.
The impact mechanism of a unit with a vertical motor may have the following malfunctions. The connecting rod mechanism has a separate bearing that is mounted on the cam of the wheel with an eccentric, but sometimes it can be located at the base of the connecting rod. In some models of rotary hammers, a plain bearing (instead of a rolling bearing) may be installed at this location, which requires constant lubrication. If it is not there, or it is already old, then this unit will wear out. During repairs, you will have to completely replace the connecting rod and eccentric barrel.
Another common problem is the firing pin broke. This malfunction can be calculated if you notice that there is no longer any impact on your hammer drill. To get to the firing pin, you will need to completely disassemble the barrel of the device. It is done as follows.
In this case, the firing pin is intact. But if it is broken, then replace it with a new one. You should also pay attention to the rubber seals and seals in the barrel body. If they are worn out, they must be replaced.
The design of the impact mechanism in a pistol-type unit is slightly different from the same-purpose mechanism installed in a barrel-type unit.
Its main difference is that the piston is driven not by a connecting rod, but by a swinging (“drunk”) bearing. Therefore, the most common breakdown of this unit is the wear of a “drunk” bearing that needs to be replaced.
The next photo shows a destroyed “drunk” bearing, which is the reason why the hammer drill stopped hammering.
The swing bearing is removed using a flat screwdriver, which you need to pick up the bracket and remove it. After this, the bearing is easily separated from the gearbox housing.
When replacing a failed bearing, you should carefully wash the gearbox, since it is in its body that fragments of a broken part may remain.
After cleaning and installing a new bearing, apply a thick layer of lubricant to this block.
Also, the reason that the device does not hit can be a broken firing pin. To get it out, you need to remove the retaining ring that is visible in the hole.
Take a small screwdriver, pick up the ring with it, and move it to the right (towards the gear).
Do the same steps on the other side of the part. Next, insert a screwdriver into the hole in the part and push through the removed internal parts of the mechanism.
After this action, you can easily get the locking ring and the housing in which the broken striker is located.
If you disassemble this case, you will see the “culprit” of the malfunction, due to which the hammer drill does not hammer.
When assembling the impact mechanism, be sure to generously apply lubricant to all parts.
In addition to breakdowns associated with the impact mechanism, other mechanical breakdowns may also occur in the hammer drill.
There are times when the unit mode switch fails. Mainly this happens due to dust clogging of this node. To repair the switch, you will need to disconnect it from the body (see how to do this above) and clean it from dirt. If you find any damage to the plastic parts of the switch, it will have to be replaced.
The reason that the device stopped working normally, namely, stopped drilling and chiseling, may lie in worn-out teeth on the rotor shaft.
If this happens, the teeth will be worn out on the intermediate helical gear.
This problem occurs when the tool is jammed or the clutch is malfunctioning. The breakdown is eliminated by replacing the intermediate gear and engine rotor.
The reason that the hammer drill does not hold the drill lies in the breakage of the chuck and the wear of its constituent parts:
You will need to disassemble the cartridge and replace problematic parts.
The reasons that the drill is stuck in the chuck of the device may be the following.
Diagram of a Bosch 2-26 rotary hammer
Video of disassembling a Bosch 2-26 rotary hammer
Difference between cartridge mounting points
SDS-plus cartridge SDS-plus quick-release chuck in disassembled state
We got to the drunken bearing
New drunken bearing The stator cover will come off.
Separation of the impact unit with rotor and stator
Bosch hammer drill rotor
Electrical part of a Bosch rotary hammer
This completes the disassembly.
I wish you success!
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The most widespread among professional builders in Russia are Bosch rotary hammers, and among amateurs the household models Bosch 2–20, 2–24, 2–26.
Rotary hammers not only work well, but are also easy to repair. You can easily find any broken part on them.
The designs of the described rotary hammers are based on the same principle: transmitting torque from the rotor to the shaft of the impact block barrel while simultaneously transmitting a translational impulse to the working tool.
Structurally, hammer drills are made according to the same design, but individual components or parts have their own characteristics.
If you know the specific differences between the models of the described Bosch rotary hammers, then disassembling and repairing them yourself will not be difficult.
Along with the originals, there are a large number of counterfeit tools on the Russian market, including Bosch rotary hammers.
Below we describe the design features of the models and how to disassemble and repair them yourself.
Operating principle of a Bosch rotary hammer The operating principle of rotary hammers is the same, but the design features differ.
The main parts used in the listed models of Bosch rotary hammers are interchangeable. This applies to the mechanical and electrical components.
But there are units made that differ in the parts used.
To repair a Bosch 2-20, 2-24, 2-26 rotary hammer, you need to know these differences. Knowledge of the design features of each rotary hammer facilitates the repair process, finding breakdowns and eliminating them.
The designs of Bosch rotary hammers are so simple that they allow you to perform simple repairs, practically with your own hands, and replace any part without contacting service departments. You must have assembly skills, have basic knowledge of electrical engineering and understand the principle of operation of a rotary hammer.
When repairing a Bosch rotary hammer, you cannot do without an electrical diagram and a disassembly diagram for the tool of the model you are going to repair.
The electrical circuits of Bosch 2-20, 2-24, 2-26 rotary hammers are almost the same. Although there are some unprincipled differences.
But mechanical blocks are equipped with parts that differ structurally from each other. The main differences are concentrated in two units: the intermediate shaft and the barrel shaft of the shock block.
The greatest differences are presented in the design of the intermediate shaft, the “drunk bearing” assembly, and the mode switch. Unprincipled features are present in the design of the barrel of the striker block, firing pin, and striker.
Let's start with the Bosch 2-20 rotary hammer.
Repairing a Bosch 2–20 rotary hammer is not possible without knowledge of the design of the tool being repaired.
The operating principle of the Bosch 2–20 rotary hammer is based on the transmission of torque from the rotor shaft, pos. 3, to the shaft of the impact block, pos. 22, through the intermediate shaft, pos. 824, while simultaneously transmitting a longitudinal impulse to the working tool.
Rotor pos. 3 transmits torque to the helical gear of the intermediate shaft pos. 824.
Diagram of a Bosch 2-20 rotary hammer
The helical gear is mounted on the intermediate shaft and transmits rotational torque to the shaft. A fixed bearing is attached to the shaft, receiving rotational torque through the clutch. Due to its design, the drunk bearing transmits translational motion to the barrel cylinder of the impact mechanism.
The intermediate shaft of a Bosch 2–20 rotary hammer consists of a rolling bearing assembly (drunk bearing), a clutch, a large helical gear, and a small spur gear.
Most often, breakdowns manifest themselves in wear of the clutch splines, which leads to the loss of rotation of the hammer drill chuck in the presence of a shock pulse.
It can be corrected by replacing the clutch or restoring the teeth of the clutch parts.
View of the intermediate shaft of the Bosch 2-20 rotary hammer
It is best to start repairing a Bosch 2–24 rotary hammer by becoming familiar with the circuit and design features of the tool being adjusted. The operating principle of the Bosch 2–24 rotary hammer is similar to the operating principle of the Bosch 2–20 rotary hammer.
The torque is transmitted to the tool mounting shaft, simultaneously with the transmission of the shock impulse. The hammer drill has three operating modes: drilling with impact, drilling without impact, impact.
The helical gear of the rotor pos. 803 transmits torque to the helical gear of the intermediate shaft pos. 826.
Diagram of a Bosch 2-24 rotary hammer The intermediate shaft of the Bosch 2-24 rotary hammer consists of a rolling bearing assembly, pos. 830, a clutch, pos. 823, and a switching part, pos. 44. Most often the clutch fails. The teeth in it wear out. Repair of the coupling consists of correcting the profile of the engagement tooth in the coupling and on the intermediate shaft.
Bosch 2-24 hammer drill intermediate shaft assembly The barrel shaft of the impact block is designed to transmit a rotational impulse with simultaneous movement of the striker.
Rotation is transmitted from the spur gear of the intermediate shaft to the large spur gear pos. 22 of the barrel shaft pos. 821.
The reciprocating motion is transmitted through the driven bearing pos. 830, the impact piston pos. 26, the striker pos. 27, the impact bolt pos. 28 to the drill fixed in the chuck pos. 756.
The design is a shaft, hollow on one side. Parts are installed on the shaft on both sides.
From the side of the cartridge mounting, a spur gear, pos. 22, is installed on the shaft and fixed on the shaft using a roller, pos. 88, and pressed against the shaft collar with a spring, pos. 80. The spring itself is fixed with a locking ring pos. 85.
The following is inserted into the cavity of the impact block barrel shaft: the assembled impact bolt pos. 28 and the impact piston. The striker pos. 27 is inserted into the impact piston pos. 26 with a new rubber ring pos. 73 placed on it. All rubber products are lubricated with the recommended lubricant.
Due to the weakening of the spring force and the locking roller falling out, the gear may rotate on the shaft. This manifests itself in the disappearance of the torque with the presence of a shock pulse.
When rubber products (sealing rings) wear out, the hammer drill stops working in the “Slotting” mode. This happens gradually. The impact force weakens as the rubber rings wear. The thing is that from the drunk bearing the movement is transferred to the impact piston pos. 26, in which the striker pos. 27 creates air pressure and acts on the impact bolt pos. 28.
If you apply a lot of force when operating a hammer drill, this can lead to the destruction of the impact bolt and jamming of the striker in the impact piston. Such malfunctions can only be eliminated by completely replacing the failed part. Learn more about troubleshooting a Bosch rotary hammer.
Repair of a Bosch 2–26 rotary hammer should begin with familiarization with the design features of the tool being adjusted. The operating principle of the Bosch 2–24 rotary hammer is similar to the operating principle of the Bosch 2–26 rotary hammer.
Diagram of a Bosch 2-26 rotary hammer
Rotation is transmitted from the rotor shaft, through the intermediate shaft, to the shaft of the impact barrel. At the same time, a bearing mounted on the intermediate shaft transmits reciprocating motion to the impact piston.
The hammer drill has three operating modes: drilling with impact, drilling without impact, impact.
The helical gear of the rotor pos. 803 transmits torque to the helical gear of the intermediate shaft pos. 823.
The intermediate shaft is similar to the shaft in the design of the Bosch 2–24 rotary hammer and is interchangeable with parts included in the intermediate shaft of the Bosch 2–24, 2–26 rotary hammers. Instructions for disassembling a Bosch rotary hammer.
The barrel shaft of the impact block is similar in design to the barrel shaft of the Bosch 2-24 rotary hammer. Breakdowns are caused by malfunctions of the same parts as in the Bosch 2-24 rotary hammer.
Scheme of the barrel shaft of the percussion mechanism Features of the shaft of the Bosch 2–26 rotary hammer are that the driven large spur gear, pos. 22, is fixed on the shaft with three pins, pos. 37, in contrast to the fixing roller in the Bosch 2–26 rotary hammer.
When disassembling the barrel shaft of the impact block of the Bosch 2-26 rotary hammer, pay attention to the method of fixing the gear. Before removing the gear, three pins must be removed. The procedure for correctly assembling a Bosch rotary hammer.
It happens that you come across counterfeit models of Bosch rotary hammers. Read more about this here.
Video: How to repair a hammer drill / 2-24 / How to change the impact bolt / Drunk bearing / Maintenance / Repair
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Bosch rotary hammer disassembly instructions
The operating principle of the Bosch 2-26 rotary hammer is no different from rotary hammers of famous brands. The rotating rotor transmits torque to the intermediate shaft of the mechanical assembly of the hammer drill, while simultaneously transmitting translational motion through the rolling bearing to the hammer hammer's impact mechanism and the impact impulse. A rotational moment with a translational shock pulse is transmitted to the working tool. This principle is implemented in all rotary hammers.
But different companies that produce rotary hammers have their own design features.
Bosch rotary hammers are considered the best in their power tool segment. But nothing is eternal.
If your Bosch 2-20, 2-24, 2-26 hammer drill has stopped working, then you can restore it yourself. You need to have basic locksmith skills and a little understanding of electrical engineering. And another important detail: the design of Bosch rotary hammers is so simple that it does not cause difficulties during repairs.
When repairing power tools, including repairing Bosch rotary hammers, strictly follow safety precautions when working with electrical appliances.
To make it easier to repair a Bosch rotary hammer, disassemble and reassemble it, study the tool assembly diagram:
Any disassembly of the Bosch 2-26 rotary hammer begins after inspection, test operation and identification of the causes of the device malfunction.
disassembly of a Bosch 2-26 rotary hammer
Since the disassembly procedure for Bosch rotary hammers is 2-20; 2-24; 2-26 is almost the same, let’s consider the order of disassembly using the Bosch 2-26 rotary hammer as an example.
Disassembling the Bosch GBH 2-26 dre hammer drill begins with disassembling the quick release chuck.
Bosch rotary hammers most often use two types of chucks: SDS-plus chucks and SDS-max chucks. The difference between them is the principle of clamping the tail part of the working organ.
The design of the Bosch hammer drill chuck differs in the design of the tool mounting rods depending on the SDS-plus or SDS-max model. In addition to the listed types of cartridges, there are SDS-top and SDS-quick cartridges.
The procedure for disassembling the Bosch 2-26 hammer drill chuck is simple:
Carefully inspect all parts of the cartridge.
SDS-plus chucks were developed specifically for drilling tools. The diameter of the tool shanks is 10 mm, the length of the working tool is in the range of 110...1000 mm. The diameter of the drills lies in the range of 4…26 mm.
With the hammer on its side, remove the mode switch pos. 832.
First, turn the switch to the “Drilling” position, press the screwdriver all the way into the end of the switch button (it is red) and turn the switch counterclockwise to an angle of 70º.
While rocking the switch handle, pull the switch handle out of the housing.
Having placed the Bosch 2-26 hammer drill vertically on the handle, unscrew the four screws pos. 90 holding the cover of the mechanical assembly housing.
Press the end of the impact shaft and remove the cover. The lid is black plastic.
Now you need to remove the barrel pos. 821 and the intermediate shaft pos. 826. They are not secured by anything.
A hammer, pos. 27, is inserted inside the cylinder, from which the rubber ring, pos. 73, must be removed. During any disassembly, rubber parts must be replaced.
At the opposite end of the cylinder, a hinge, pos. 29, and two flat washers, pos. 41, are inserted.
The intermediate shaft is disassembled by removing the shaft, pos. 24, and pulling out the “drunk bearing” from the housing, pos. 77.
Bearings are removed with pullers or manually using a device.
Bosch rotary hammers are very reliable. But there are malfunctions that are practically not encountered in practice. Below is one of them.
If the hammer drill has stopped hammering, but still allows you to drill, the most likely reason may be the destruction of a “drunk bearing”. This malfunction does not occur often and is not easy to find.
To fix it, you don’t need to go to a repair shop. Any person with the slightest knowledge of mechanics can fix such a malfunction.
First you need to disassemble the Bosch hammer drill down to the intermediate shaft. The disassembly procedure is given above.
By removing the intermediate shaft, you will get to the “drunk bearing”. The destruction of a rolling bearing is indicated by a broken race, scattered balls, or pieces of the race.
You take out the bearing, remove dirt and all parts of the destroyed mechanism.
You buy a new “drunk bearing”, and, having lubricated all the parts with new grease, replace and reassemble them in the reverse order of the disassembly steps.
Disassembling the Bosch 2-26 rotary hammer, its electrical part, begins by removing the back cover on the rotary hammer handle by unscrewing three screws.
The next step is to remove the reverse switch.
Turn it to neutral and lift it towards you. The reverse switch is removed.
To remove the stator cover, you need to hold the mechanical unit in your right hand and the stator housing in your left hand, drag them in different directions, shaking them.
The stator cover will come off.
To separate the rotor from the mechanical assembly, it is enough to drag these parts in different directions. The rotor is secured to the mechanical assembly by a small helical gear that is inserted into contact with a large helical gear of the mechanical assembly.
The rotor has been freed and you can carefully inspect the condition of the commutator and bearings.
To remove the stator, simply remove the protective plastic protective casing and tap the end of the housing into which the stator is inserted with a wooden block or mallet. Before doing this, do not forget to unscrew the two screws securing the stator to the housing.
The stator has been removed, the rotor has been removed, you can begin to inspect them and defect all the parts that make up the electrical part of the Bosch rotary hammer.
When inspecting a disassembled Bosch 2-26 rotary hammer, pay special attention to the condition of the carbon brushes, plaque on the brush holders and the reliability of their fastening, the integrity of the reverse switch contacts, and the condition of the wire at the point of entry into the rotary hammer.
The length of the brushes should not be shorter than 8 mm. There should be no traces of sparking or carbon dust from the brushes on the brush holders; there should be no burnouts or damage to the contacts on the contacts of the reverse switch of the Bosch 2-26 rotary hammer.
This completes the disassembly.
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Nothing lasts forever. And the most reliable Bosch rotary hammers begin to break over time. But any malfunction can be repaired with your own hands if you have detailed instructions for performing repair work. Below we offer you a guide to troubleshooting Bosch rotary hammers and a method for eliminating them. The main causes of breakdowns are:
Conventionally, faults can be divided into mechanical and electrical.
When mechanical malfunctions occur in the operation of the tool, an extraneous unpleasant sound appears, sparking intensifies in the collector area, a burning smell appears, the tool heats up excessively, its power drops depending on the duration of operation and the impact on the material.
We will look at all the faults in the diagram of the Bosch 2-26 rotary hammer. Other models, such as Bosch 2-20, 2-24, differ in the design of the intermediate shaft and the installation of various bearings.
The hammer drill does not hammer under load or in idle mode for the following reasons:
The main reasons why a rotary hammer hammers but does not drill are:
The main reasons why a hammer drill does not chisel or drill are:
Now let's talk about everything in order
Wear of rubber rings on the striker, striker, piston.
This reason appears gradually as the rubber rings wear out. At first the blow weakens, then disappears altogether.
The malfunction is eliminated by replacing the indicated rubber rings with new ones.
For any repair of rotary hammers or their components, all rubber products must be replaced.
Repair kit for rubber sealing rings for a Bosch 2-26 rotary hammer
If the drunk bearing pos. 830 is destroyed, the rotational movement of the intermediate shaft cannot be converted into the translational movement of the cylinder in the impact mechanism.
Eliminated by completely replacing the rolling bearing.
Friction bearing
There are cases when the striker in the cylinder, pos. 26, gets stuck, which leads to destruction of the cylinder and the impossibility of creating air pressure in the barrel of the striker mechanism. And the second reason: destruction or breakage of the striker pos. 28, leading to distortion of the part and the impossibility of transmitting the shock impulse. Breakdowns are eliminated by completely replacing failed parts.
The firing pin is jammed in the piston, the piston is destroyed
The malfunction can be eliminated by repairing the clutch or completely replacing it. When making repairs, the worn teeth on the clutch are filed down. To correct this defect, a round needle file and a drill are used. The coupling is clamped in the hand, and the tooth profiles are straightened using a drill with an appropriate file. The splines on the intermediate shaft are modified in the same way.
Restoring the teeth of the intermediate shaft clutch When the pressure force of the spring pos. 50 decreases, the clutch slips on the intermediate shaft without transmitting rotation from the small spur gear to the large gear pos. 22 of the barrel shaft pos. 821 of the impact mechanism. By the way, on different Bosch models, clutches are designed differently.
Details of the torque and translational impulse transmission unit The large gear, pos. 22, is attached to the barrel shaft, pos. 01, with a roller, pos. 88, pressed against the shaft collar with a conical spring, pos. 80, and secured with a retaining ring, pos. 85.
The reason may be a weakening of the force of the conical spring pos. 80, destruction of the locking ring pos. 85, or loss of the fixing roller pos. 88.
Gear pos.22 on the shaft pos.01 of the barrel pos.821 of the shock block assembly
Bosch rotary hammers use two types of chucks: SDS-plus and SDS-max. The difference is in the design of the locking mechanism.
The reason is the wear of the antennae of the chuck raster bushing, which makes it impossible to transmit the shock pulse to the working tool of the hammer drill.
Tool shanks for hammer drill chucks Bosch 2-26
The gears rotate and the teeth on one of them, usually the small one, are cut off.
When the working tool jams and the clutch does not work properly, the gear teeth on the hammer drill shaft and the intermediate shaft wear out or are completely destroyed.
In this case, the rotor or large gear of the intermediate shaft is completely changed.
Bosch 2-26 hammer drill rotor with cut splines
The reasons for a non-working electric motor may be:
The listed malfunctions are eliminated by repair (manually rewinding the windings, replacing the commutator and desoldering the winding leads) or replacing the rotor, stator, and carbon electric brushes with new ones. The majority of malfunctions in the electrical part of the Bosch 2-26 rotary hammer are confirmed by increasing sparking in the collector area.
The length of serviceable electric brushes cannot be less than 8 mm. When replacing one brush, the second should change automatically.
The rotor or stator windings can be rewound yourself at home.
Burnt rotor manifold of a Bosch rotary hammer
The cause of this malfunction is a break in the wire supplying power to the electric motor. Most often, a break occurs at the point where the cable enters the hammer drill. The wire should be replaced with a new one or repaired. The malfunction can be determined using a tester. If there is no tester, the fault can be found using the power phase and a screwdriver with a neon indicator lamp. Connecting the power wires one by one, at the other end, using a neon screwdriver, determine the presence or absence of a phase.
The power button for the hammer drill does not work. Determined by a short circuit tester.
Most often, the failure of the punch button is caused by a short circuit of the filter capacitor. It is best to replace the button with a new one.
Power cord pos. 5 at the entrance to the tool Failure of a rotary hammer in the electrical part is accompanied by the appearance of a burning smell, strong heating of the tool during operation, the appearance of large sparks in the area of the rotor manifold of the rotary hammer, and poor operation of the reverse switch.
The operation of the hammer drill is influenced by the condition of the carbon brushes, the reliability of the fastening of the brush holders and their correct installation.
A burning smell appears when the stator or rotor windings are short-circuited.
A drop in power of a rotary hammer with increasing load is typical when there is a break in the rotor windings or when the carbon brushes are short.
The heating of the hammer most often results from a short interturn circuit in the stator or rotor.
Large sparking in the commutator area is caused by interturn closure of the rotor or burnout of the commutator lamellas.
Malfunction of the reverse switch occurs due to burning of its contacts.
But the main reason for all breakdowns is untimely implementation of technical routine maintenance and replacement of carbon brushes.
Carbon brushes require replacement after 70 hours of operation or when worn down to 8 mm in length.
General view and dimensions of the carbon brushes of the Bosch rotary hammer
We have given the main reasons why Bosch rotary hammers fail. We may not have described all the breakdowns of Bosch rotary hammers.
If you know other faults with Bosch 2-20, 2-24, 2-26 rotary hammers, please share with us.
I wish you success!
Video of replacing the raster bushing in the Bosch 2-26 cartridge Video of replacing the armature in a Bosch 2-26 rotary hammer
A hammer drill is a tool designed specifically for drilling or chiseling concrete, brick or other hard material. The first hammer drill was invented by Bosch in 1932, which is why today this company is the most popular in the power tool market. Please note that Bosch markets power tools in two colors: blue and green. Blue hammer drills are intended for professional use and can withstand heavy loads, while a green hammer drill is a home power tool.
In order to make a hole in concrete, more impact force is required, which is why hammer drills are shaped like a chisel. The drill is subjected to an impact force, which is transmitted to the material and destruction occurs. The drill is designed in such a way that dust and waste are removed and do not impede further drilling.
The Bosch hammer drill consists of a built-in electro-pneumatic or electromechanical impact mechanism, so the intensity of drilling does not depend in any way on the force of pressing on the hammer. Rotary hammers are divided into three main classes: light (1-3 kg), medium (4-5 kg) and heavy (6-12 kg).
|
Class perforated ratora, |
Instru- cop |
Nominal |
Drilling diameter in concrete with drills, |
Force blow, |
|||
|
ness, |
number |
number defense |
SDS plus | SDS max | |||
| 2 | SDS plus | ||||||
| 4 | SDS plus | 750 | 4550 | 820 | 4-30 | 3,5 | |
| 5 | SDS max | 950 | 3200 | 360 | 12-40 | 40-55 | 5,4 |
| 8 | SDS max | 1050 | 2650 | 255 | 12-40 | 40-65 | 7,5 |
| 10 | SDS max | 1500 | 2250 | 250 | 12-40 | 45-80 | 17 |
The impact force of a rotary hammer is measured in joules. To understand how much 1 J is, imagine the picture: a load weighing 1 kg falls from a height of 1 m in 1 second. This will be the impact force of 1 J.
As already mentioned, the main part of the hammer drill is an electro-pneumatic impact mechanism. The rotary mechanism transmits the rotation of the engine to the shaft, which converts the rotational motion into oscillatory motion, thanks to the cylinder. When the cylinder returns back, the striker moves backward. Thus, tension is formed between the cylinder and the striker, in the form of compressed air, which is a kind of spring that prevents the striker from hitting the cylinder.
The impact mechanism of a Bosch hammer drill may turn itself off during idling, when there is no pressure on the power tool, but as soon as you press the hammer, it will start working again. When working with a rotary hammer, it is worth remembering that when compressed, the air becomes very hot, so after long-term continuous operation of the rotary hammer, it is worth ventilating the entire mechanism at idle.
When drilling concrete, it is very common to hit reinforcement, so the Bosch rotary hammer is equipped with a safety clutch to prevent the drill from blocking. When the drill reaches the reinforcement and is blocked, then the coupling disconnects the drill from the electric motor. Therefore, when purchasing a Bosch rotary hammer, ask the seller about the availability of this function.
The Bosch rotary hammer can be used for drilling, drilling and chiselling, chiselling and variolets. Variolok is an opportunity to fix the chisel in any of the 36. possible position.
The most widespread among professional builders in Russia are Bosch rotary hammers, and among amateurs the household models Bosch 2-20, 2-24, 2-26. Rotary hammers not only work well, but are also easy to repair. You can easily find any broken part on them.
The designs of the described rotary hammers are based on the same principle: transmitting torque from the rotor to the shaft of the impact block barrel while simultaneously transmitting a translational impulse to the working tool.
Structurally, hammer drills are made according to the same design, but individual components or parts have their own characteristics.
If you know the specific differences between the models of the described Bosch rotary hammers, then disassembling and repairing them yourself will not be difficult.
Along with the originals, there are a large number of counterfeit tools on the Russian market, including Bosch rotary hammers.
Below we describe the design features of the models and how to disassemble and repair them yourself.
The operating principle of rotary hammers is the same, but the design features differ.
The main parts used in the listed models of Bosch rotary hammers are interchangeable. This applies to the mechanical and electrical components.
But there are units made that differ in the parts used.
To repair a Bosch 2-20, 2-24, 2-26 rotary hammer, you need to know these differences. Knowledge of the design features of each rotary hammer facilitates the repair process, finding breakdowns and eliminating them.
The designs of Bosch rotary hammers are so simple that they allow you to perform simple repairs, practically with your own hands, and replace any part without contacting service departments. You must have assembly skills, have basic knowledge of electrical engineering and understand the principle of operation of a rotary hammer.
When repairing a Bosch rotary hammer, you cannot do without an electrical diagram and a disassembly diagram for the tool of the model you are going to repair.
The electrical circuits of Bosch 2-20, 2-24, 2-26 rotary hammers are almost the same. Although there are some unprincipled differences.
But mechanical blocks are equipped with parts that differ structurally from each other. The main differences are concentrated in two units: the intermediate shaft and the barrel shaft of the shock block.
The greatest differences are presented in the design of the intermediate shaft, the “drunk bearing” assembly, and the mode switch. Unprincipled features are present in the design of the barrel of the impact block, firing pin, and striker.
Let's start with the Bosch 2-20 rotary hammer.
Repairing a Bosch 2-20 rotary hammer is not possible without knowledge of the design of the tool being repaired.
The operating principle of the Bosch 2-20 rotary hammer is based on the transmission of torque from the rotor shaft pos. 3 to the impact block shaft pos. 22 through the intermediate shaft pos. 824, while simultaneously transmitting longitudinal impulse to the working tool.
Rotor pos. 3 transmits torque to the helical gear of the intermediate shaft pos. 824.
The helical gear is mounted on the intermediate shaft and transmits rotational torque to the shaft. A fixed bearing is attached to the shaft, receiving rotational torque through the clutch. Due to its design, the drunk bearing transmits translational motion to the barrel cylinder of the impact mechanism.
The intermediate shaft of a Bosch 2-20 hammer drill consists of a rolling bearing assembly (drunk bearing), a clutch, a large helical gear, and a small spur gear.
Most often, breakdowns manifest themselves in wear of the clutch splines, which leads to the loss of rotation of the hammer drill chuck in the presence of a shock pulse.
It can be corrected by replacing the clutch or restoring the teeth of the clutch parts.
It is best to start repairing a Bosch 2-24 rotary hammer by becoming familiar with the circuit and design features of the tool being adjusted. The operating principle of the Bosch 2-24 rotary hammer is similar to the operating principle of the Bosch 2-20 rotary hammer.
The torque is transmitted to the tool mounting shaft, simultaneously with the transmission of the shock impulse. The hammer drill has three operating modes: drilling with impact, drilling without impact, impact.
The helical gear of the rotor pos. 803 transmits torque to the helical gear of the intermediate shaft pos. 826.
The intermediate shaft of a Bosch 2-24 rotary hammer consists of a rolling bearing assembly, pos. 830, a clutch, pos. 823, and a switching part, pos. 44. Most often, the clutch fails. The teeth in it wear out. Repair of the coupling consists of correcting the profile of the engagement tooth in the coupling and on the intermediate shaft.
The barrel shaft of the impact block is designed to transmit a rotational impulse with simultaneous movement of the striker.
Rotation is transmitted from the spur gear of the intermediate shaft to the large spur gear pos. 22 of the barrel shaft pos. 821.
The reciprocating motion is transmitted through the driven bearing pos. 830, the impact piston pos. 26, the striker pos. 27, the impact bolt pos. 28 to the drill fixed in the chuck pos. 756.
The design is a shaft, hollow on one side. Parts are installed on the shaft on both sides.
From the side of the cartridge mounting, a spur gear, pos. 22, is installed on the shaft and fixed on the shaft using a roller, pos. 88, and pressed against the shaft collar with a spring, pos. 80. The spring itself is fixed with a locking ring pos. 85.
The following is inserted into the cavity of the impact block barrel shaft: the assembled impact bolt pos. 28 and the impact piston. The striker pos. 27 is inserted into the impact piston pos. 26 with a new rubber ring pos. 73 placed on it. All rubber products are lubricated with the recommended lubricant.
Due to the weakening of the spring force and the locking roller falling out, the gear may rotate on the shaft. This manifests itself in the disappearance of the torque with the presence of a shock pulse.
When rubber products (sealing rings) wear out, the hammer drill stops working in the “Slotting” mode. This happens gradually. The impact force weakens as the rubber rings wear. The thing is that from the drunk bearing the movement is transferred to the impact piston pos. 26, in which the striker pos. 27 creates air pressure and acts on the impact bolt pos. 28.
If you apply a lot of force when operating a hammer drill, this can lead to the destruction of the impact bolt and jamming of the striker in the impact piston. Such malfunctions can only be eliminated by completely replacing the failed part. Learn more about troubleshooting a Bosch rotary hammer.
Repair of a Bosch 2-26 rotary hammer should begin with familiarization with the design features of the tool being adjusted. The operating principle of the Bosch 2-24 rotary hammer is similar to the operating principle of the Bosch 2-26 rotary hammer.
Rotation is transmitted from the rotor shaft, through the intermediate shaft, to the shaft of the impact barrel. At the same time, a bearing mounted on the intermediate shaft transmits reciprocating motion to the impact piston.
The hammer drill has three operating modes: drilling with impact, drilling without impact, impact.
The helical gear of the rotor pos. 803 transmits torque to the helical gear of the intermediate shaft pos. 823.
The intermediate shaft is similar to the shaft in the design of the Bosch 2-24 rotary hammer and is interchangeable with parts included in the intermediate shaft of the Bosch 2-24, 2-26 rotary hammers. Instructions for disassembling a Bosch rotary hammer.
The barrel shaft of the impact block is similar in design to the barrel shaft of the Bosch 2-24 rotary hammer. Breakdowns are caused by malfunctions of the same parts as in the Bosch 2-24 rotary hammer.
Features of the Bosch 2-26 rotary hammer shaft are that the driven large spur gear, pos. 22, is fixed on the shaft with three pins, pos. 37, in contrast to the locking roller in the Bosch 2-26 rotary hammer.
When disassembling the barrel shaft of the impact block of the Bosch 2-26 hammer drill, pay attention to the method of fixing the gear. Before removing the gear, three pins must be removed. The procedure for correctly assembling a Bosch rotary hammer.
Knowing the differences between the above models of Bosch rotary hammers will allow you to quickly disassemble the tool and replace faulty parts. To do this, you do not need to contact customer service.
Structurally, Bosch rotary hammers are so simple that they allow you to carry out repairs of almost any complexity.
All you need is desire and basic knowledge of mechanics.
It happens that you come across counterfeit models of Bosch hammer drills. Read more about this.
Video: How to repair a hammer drill / 2-24 / How to change the impact bolt / Drunk bearing / Maintenance / Repair
The operating principle of the Bosch 2-26 rotary hammer is no different from rotary hammers of famous brands.
The rotating rotor transmits torque to the intermediate shaft of the mechanical assembly of the hammer drill, while simultaneously transmitting translational motion through the rolling bearing to the hammer hammer's impact mechanism and the impact impulse. A rotational moment with a translational shock pulse is transmitted to the working tool. This principle is implemented in all rotary hammers.
But different companies that produce rotary hammers have their own design features.
Bosch rotary hammers are considered the best in their power tool segment. But nothing is eternal.
If your Bosch 2-20, 2-24, 2-26 hammer drill has stopped working, then you can restore it yourself. You need to have basic locksmith skills and a little understanding of electrical engineering.
And another important detail: the design of Bosch rotary hammers is so simple that it does not cause difficulties during repairs.
When repairing power tools, including repairing Bosch rotary hammers, strictly follow safety precautions when working with electrical appliances.
To make it easier to repair a Bosch rotary hammer, disassemble and reassemble it, study the tool assembly diagram:
Any disassembly of the Bosch 2-26 rotary hammer begins after inspection, test operation and identification of the causes of the device malfunction.
Video of disassembling a Bosch 2-26 rotary hammer
Since the disassembly procedure for Bosch rotary hammers is 2-20; 2-24; 2-26 is almost the same, let’s consider the order of disassembly using the Bosch 2-26 rotary hammer as an example.
Disassembling the Bosch GBH 2-26 dre hammer drill begins with disassembling the quick release chuck.
Bosch rotary hammers most often use two types of chucks: SDS-plus chucks and SDS-max chucks. The difference between them is the principle of clamping the tail part of the working organ.
The design of the Bosch hammer drill chuck differs in the design of the tool mounting rods depending on the SDS-plus or SDS-max model. In addition to the listed types of cartridges, there are SDS-top and SDS-quick cartridges.
The procedure for disassembling the Bosch 2-26 hammer drill chuck is simple:
Carefully inspect all parts of the cartridge.
SDS-plus chucks were developed specifically for drilling tools. The diameter of the tool shanks is 10 mm, the length of the working tool is in the range of 110...1000 mm. The diameter of the drills lies in the range of 4…26 mm.
With the hammer on its side, remove the mode switch pos. 832.
First, turn the switch to the “Drilling” position, press the screwdriver all the way into the end of the switch button (it is red) and turn the switch counterclockwise to an angle of 70º.
While rocking the switch handle, pull the switch handle out of the housing.
Having placed the Bosch 2-26 hammer drill vertically on the handle, unscrew the four screws pos. 90 holding the cover of the mechanical assembly housing.
Press the end of the impact shaft and remove the cover. The lid is black plastic.
Now you need to remove the barrel pos. 821 and the intermediate shaft pos. 826. They are not secured by anything.
A hammer, pos. 27, is inserted inside the cylinder, from which the rubber ring, pos. 73, must be removed. During any disassembly, rubber parts must be replaced.
At the opposite end of the cylinder, a hinge, pos. 29, and two flat washers, pos. 41, are inserted.
The intermediate shaft is disassembled by removing the shaft, pos. 24, and pulling out the “drunk bearing” from the housing, pos. 77.
Bearings are removed with pullers or manually using a device.
Bosch rotary hammers are very reliable. But there are malfunctions that are practically not encountered in practice. Below is one of them.
If the hammer drill has stopped hammering, but still allows you to drill, the most likely reason may be the destruction of a “drunk bearing”. This malfunction does not occur often and is not easy to find.
To fix it, you don’t need to go to a repair shop. Any person with the slightest knowledge of mechanics can fix such a malfunction.
First you need to disassemble the Bosch hammer drill down to the intermediate shaft. The disassembly procedure is given above.
By removing the intermediate shaft, you will get to the “drunk bearing”. The destruction of a rolling bearing is indicated by a broken race, scattered balls, or pieces of the race.
You take out the bearing, remove dirt and all parts of the destroyed mechanism.
You buy a new “drunk bearing”, and, having lubricated all the parts with new grease, replace and reassemble them in the reverse order of the disassembly steps.
Disassembling the Bosch 2-26 rotary hammer, its electrical part, begins by removing the back cover on the rotary hammer handle by unscrewing three screws.
The next step is to remove the reverse switch.
Turn it to neutral and lift it towards you. The reverse switch is removed.
To remove the stator cover, you need to hold the mechanical unit in your right hand and the stator housing in your left hand, drag them in different directions, shaking them.
The stator cover will come off.
To separate the rotor from the mechanical assembly, it is enough to drag these parts in different directions. The rotor is secured to the mechanical assembly by a small helical gear that is inserted into contact with a large helical gear of the mechanical assembly.
The rotor has been freed and you can carefully inspect the condition of the commutator and bearings.
To remove the stator, simply remove the protective plastic protective casing and tap the end of the housing into which the stator is inserted with a wooden block or mallet. Before doing this, do not forget to unscrew the two screws securing the stator to the housing.
The stator has been removed, the rotor has been removed, you can begin to inspect them and defect all the parts that make up the electrical part of the Bosch rotary hammer.
When inspecting a disassembled Bosch 2-26 rotary hammer, pay special attention to the condition of the carbon brushes, plaque on the brush holders and the reliability of their fastening, the integrity of the reverse switch contacts, and the condition of the wire at the point of entry into the rotary hammer.
The length of the brushes should not be shorter than 8 mm. There should be no traces of sparking or carbon dust from the brushes on the brush holders; there should be no burnouts or damage to the contacts on the contacts of the reverse switch of the Bosch 2-26 rotary hammer.
This completes the disassembly.
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