How to Disassemble a Bosch 2800 Rotary Hammer

The hammer drill is a tool that experiences great mechanical stress. For normal operation of the unit, routine inspection and repair should be carried out regularly. If you do not take into account such rules, then after a short time the device will become unusable.

Bosch is one of the world leaders in the production of power tools, including rotary hammers. To service such equipment requires the participation of certified service centers. Minor problems can be repaired by yourself.

Specifications

The Bosch rotary hammer is a tool that is especially popular among professional builders. Serious repairs of these units have to be infrequently, but, like any equipment, rotary hammers from Bosch over time require preventive repairs.

Units from Bosch are divided into two large classes:

• punchers in which the engine is horizontal (the layout of the barrel and the anchors are parallel);
• punchers, where the engine is upright. in this case, all working nodes are located at a certain angle.

The rotary hammer has mechanical and electrical units. The second block consists of such nodes:

• engine;
• engine control device;
• button and switch block;
• interchangeable cord;
• noise reduction unit.

The mechanical assembly is assembled from the following elements:

• gearbox (mounted directly on the engine shaft);
• shock impulse mechanism;
• cartridge, brushes, anchor;
• clutch that provides grip.

Also, together with the puncher itself, various interchangeable removable elements are included in the kit:

There is also a stand-alone vacuum cleaner that works with the unit. The tool is in a convenient case.

Benefits

The performance of the Bosch rotary hammer is characterized by three criteria.

• The number of spindle revolutions (from 650 to 2200 revolutions per minute).
• The power of the impact is directly related to the characteristics of the engine, the weight of the striker, the distance of its working stroke. This is one of the main indicators of tool quality. It varies from 1.5 J to 14 J. The most expensive models can cost 50 thousand rubles.
• The impact frequency is characterized by the number of mechanical impulses per unit of time (one minute). In models from Bosch, the rate can range from 1000 to 5600 beats per minute.

In models from Bosch, all three parameters are organically combined, which allows us to call the punchers from this manufacturer the best in the world.

Bosch rock drill models can do the following:

• rotation;
• hit;
• spin and hit at the same time.

In the "Rotation" mode, various materials are drilled: metal, wood. In the “Impact” mode, the device can work like a jackhammer. perforators are especially effective in dismantling construction work. The last function, “Rotation and Impact”, has proven itself in drilling particularly hard materials (granite, concrete, tile).

disadvantages

The main disadvantage of the Bosch tool is its rather high price.

Bosch rotary hammers are divided into types:

• Household models (engines 410-720 watts). These units have three standard modes, their weight is small (no more than six kilograms).

The most popular hammer drill of this family is considered Bosch PBH 2800 RE.

The letter "P" defines the model as an aggregate for use in domestic conditions. Typically, such a tool is marked with a green color. The disadvantage of such machines is not the best cooling and increased returns.

The advantages of such models are much greater than the disadvantages, among which are worth mentioning:

• average price;
• light weight;
• compact sizes;
• good performance;
• reliability in work.

• The second big class of tools from Bosch is professional rotary hammers with a power of 810 watts and more, their weight ranges from 6 to 12.5 kilograms.

The most popular hammer drill of this class is GBH 8–45 DV, it has a power of more than one and a half thousand watts, there are only two operating modes: punch, as well as drilling and punch.

The advantages of this model are efficient cooling of the unit, minimal vibration, and reliable operation. If we talk about the shortcomings, we should mention the large sizes of such devices and a high price.

• Cordless Hammers from "Bosch" can work from a network of 220 volts. Also available are devices that operate wirelessly from the battery. Lithium and cadmium multiply charged power sources are used. Such punchers are extremely necessary in locations where there is no power from the network. Professional cordless rotary hammers can operate up to 6-8 hours.

• Everything vacuum cleaner units from Bosch are equipped with a useful device. a dust collector. Such a device significantly extends the life of the unit. The manufacturer also comes with a vacuum cleaner that operates from an autonomous power source.

• Hammer drill. It has such technical indicators:

• power. up to 1.6 kW;
• rotation. no more than 3980 revolutions;
• the number of strokes is about 50 per minute.

The Anti-rotation technology is used, which effectively protects against overloads. With this tool, concrete of low density can be drilled. The rotation speed does not change both at idle and when a load appears. Such a drill can also drill masonry and a dense beam.

• Pneumatic hammer drill Bosch is equipped with an engine power of 750 watts, while the speed reaches 855 rpm. Holes can be drilled in medium-density concrete (up to 25 mm thick), dense wood, steel (15 mm). Weight. about three kg.

How to choose?

To choose the right hammer for the home, it is worth considering several important factors. For homework, units whose power does not exceed six hundred watts are suitable.

In the work of any punch, the layout of the engine is important. If the motor is located in a horizontal plane, then such a device is applicable for small narrow drilling. The engine in such models is assembled along the shock axis, which does not allow it to cool rapidly.

Video: How to Disassemble a Bosch 2800 Rotary Hammer

If a large amount of work is done, then such a power unit should quite often “rest” (on average, every 15-20 minutes). Otherwise, it will simply overheat and become unusable.

The vertical layout of the engine increases the power of the hammer, and there is no need to constantly cool the engine. Such devices are in demand among professional builders, the performance of such drills is high.

When choosing, you should look at the markings. If the inscription SDS is present, then this tool can work on concrete. When choosing a punch, you should read the instructions, consult with the seller, who can give valuable practical advice.

Also on Bosch rotary hammers there are such letters: PBH or GBH.

• G means that the unit is suitable for professional use;
• R. it is a letter with which household units are marked.

The numbers show how much the punch weighs (example: 3-30, 2-42). Letters in words:

• d. used for chiselling;
• f. use with a mixed cartridge;
• r. there is a reverse.

Bosch hammer drills are also found. Acquiring such a tool is not recommended.

How to disassemble and repair?

The appearance of malfunctions in the punch is characterized by sound signals:

• a rattle appears;
• strange noise background;
• the engine starts to work in roars;
• power is lost;
• there is a smell of burning wiring;
• high vibration appears.

Most often, such failures are found in the Bosch rotary hammer:

• failure of the switches;
• wear of the rubber coupling between the striker and the striker;
• the cessation of the impact mechanism itself;
• disruption of gears or their wear;
• defect of the clamping unit. it ceases to hold the drill;
• violation of the electrical connection.

Also, defects that occur in the wiring provoke the appearance of sparks and overheating of the unit.

Electrical failures are as follows:

• the engine does not work;
• violation of contacts;
• burnout of the winding.

To fix mechanical and electrical problems with your own hands, you need to disassemble the hammer. All such devices are made on the same principle. Repair of a Bosch rotary hammer is not much different from disassembling a similar assembly in any other rotary hammer.

Disassembly of the instrument should be photographed using a telephone, so that then everything is correctly assembled.

The start of dismantling begins with the cartridge: you should remove the rubberized boot, then the retaining ring, only after that the plastic boot will be removed. Then you need to find the ball (located under the washer), carefully remove it. The cause of the malfunction often lies precisely in the wear of these parts.

The puncher body is dismantled. for this, the switch that controls the operating modes is removed. The switch is placed in the position of "Impact" (there is a hammer symbol on the case). If such a designation is missing, then put a switch in the designation "Impact-drilling". After that, a small button is pressed, which is located on the switch itself. It should be slightly turned down the symbol icon depicting a hammer, and a click should occur. After that, the switch rises with a screwdriver, reaches for itself.

In some models, the switch is attached to the case with screws, so it will be enough just to unscrew them.

If you think that the problem lies precisely in the electrical unit, then the following steps should be taken:

• Screws are unscrewed, the back cover is removed;
• the fasteners that fix the network cable are removed;
• the Start button is dismantled;
• all fasteners that hold the stator wires and anchors are dismantled;
• brushes are taken out;
• the electrical and mechanical unit is disconnected. for this it is enough to unscrew a few bolts;
• the rotor is removed, the bearings are inspected;
• the air intake is removed;
• the stator is removed.

A slightly different design is present in rotary hammers, in which the electric drive is arranged vertically. In this case, the handle is first dismantled, then the bolts connecting the case to the engine are removed with a screwdriver.

Often, replacement of the engine brushes is required, the appearance of such a malfunction is not difficult to determine: it manifests itself as the smell of burned wiring, plentiful sparking. This defect is one of the most common.

The presence of sparks indicates that bearings must be replaced, there may also be defects in the insulation of the rotor and stator. This option is also possible: the collector plates burned out. Damage to the stator also generates abundant sparking, and only under one electrode.

You can’t do without a tester here, you should ring both the rotor and the stator. It will be necessary to measure all the parameters step by step, especially carefully. the resistance level on the windings (the resistance should be constant). If it is established that all problems are in the rotor and stator, then you should give the unit to a service center. Only an experienced specialist can fix such a malfunction.

The easiest repair is brush replacement. It is enough just to open the cover. the brushes are in special grooves-holders.

Brushes are differentiated into several types.

• Graphite brushes. Such brushes are reliable and can work without interference for a long time. Of the disadvantages, it can be noted that their wear is uneven, which negatively affects the collector.
• Carbon graphite brushes more durable, replacement is required if 30% of the material is worn out. Even if one brush is normal and the other is completely worn out, then a replacement of both is required.

When working with brushes, attention should be paid to the spring and contact mount. The spring must be firmly fixed. if it comes off, the engine will be damaged. A weak spring will not provide the necessary fit, which will adversely affect the quality of the contact.

After completion of work, all units should be cleaned of graphite chips; in this case, alcohol or vodka should be used. Then the electrodes are fitted to the collector. In this case, an emery cloth is used with minimal grit, which is applied to the collector and lapping of the electrode occurs with small rotational vibrations.

When the electrode area is slightly rounded, this will be considered a full contact. Such contact will guarantee a good fit to the surface of the collector plates.

The impact mechanism depends on what kind of rotary hammers is being repaired. Barrel units have a vertical layout of the engine, the shock block is present on the basis of the crank mechanism (KShM). The connecting rod mechanism contains only one bearing. it is mounted on the cam of the wheel with an eccentric.

There are also designs where the bearing is attached directly to the connecting rod base. During repairs, as a rule, the connecting rod and cam are changed.

Another type of damage is the failure of the striker. To fix this malfunction is simple: the unit is working, but there is no impact. To eliminate the defect, it is necessary to disassemble the barrel. The striker is easy to replace. Also, rubber pads often wear out. they must also be replaced.

Pistol perforators have a different design: the piston does not move with a connecting rod, but as a result of a dynamic swinging bearing. Such a bearing is subjected to maximum loads and wears out frequently. The bearing will need to be changed. It is not difficult to remove the bearing using a screwdriver. it will be enough to hook the bracket and pull it out.

During the work should be stocked with rags, as well as alcohol. it will be necessary to rinse the gearbox.

Other mechanical malfunctions can occur in the failure of the mode switch. In this case, it should be cleaned. If after that it still does not function, then it must be replaced. If gears with an oblique tooth fail, then the punch ceases to “hammer”, Also, these components must be replaced.

There are 2 reasons for gear failure: the clutch has broken or the gear has failed. Replacement of these elements will be required.

If the drill flies out of the cartridge, then there are several reasons:

• there was a deformation of the ball elements;
• The safety ring has “grown old”;
• deformed spring, which fixes.

With such malfunctions, you will have to disassemble the cartridge and look at all the details.

If the drill gets stuck, then this indicates that the grease on the shank is dry or not enough. To eliminate such a malfunction, it will be necessary to drip oil into the socket.

The drill also gets stuck due to the "hardening" of the accumulated dust. In this case, a little engine oil should also be added.

If a standard drill was used in the puncher, then it will need to be treated with special WD-40 solutions. Then wait a few minutes, then gently loosen the drill in different directions.

If the shank is riveted, then in this case it will be necessary to add a special fluid, and then try to pull the tool out of the socket.

See how to fix a Bosch rotary hammer in the next video.