The Makita hammer has stopped hammering but is drilling the reason

“Drunk” bearing

It is mounted on the shaft at an angle and drives the piston. If there is a depletion or destruction, the bearing must be replaced.


To remove a damaged bearing, the technician uses a specialized puller to detach the retaining ring (if holding the part). A rotational movement along the thread “unscrews” the old bearing from the shaft. The new part is hammered onto the shaft with a wooden or rubber “soft” hammer, after which it is lubricated.

Instrument device and its mechanism

The functional purpose of the punch is determined by its internal structure.

Hammer drill Makita HR2470 fix mechanical problem

The reinforced impact-rotational mechanism of the tool is the so-called “swing bearing” or “crank connecting rod”, which, rotating from the engine, transmit vibrations to the pneumatic pistons (or piston), after which the air injected in the pistons is pushed with a blow by the firing pin with a nozzle.

hammer, stopped, drilling, reason

The impact force of 17-20 kilojoules and the parallel rotation of the displacer due to the transmission gear ensures the entry of the chisel or drill into the material of high density. It is necessary for punching through holes or chipping holes for electrical wiring or plumbing pipes.

The drill does not hold in the chuck and flies out

In this case, the malfunction should be looked for in the chuck collet mechanism. it is disassembled and checked in place whether the ball bearings are in place, the retaining ring or the retaining spring has not opened or has weakened.

How to repair a barrel instrument?

The design of electric rock drills varies depending on the location of the motor. It happens:

  • vertical (or barrel). in it, the engine stands vertically in relation to the rotational-shock axis;
  • horizontal, that is, the motor is parallel to the axis of rotation.

Dismantling the barrel puncher is easier than the horizontal analogue. two device covers give separate access to the mechanical and electrodynamic parts. The upper casing exposes the gear unit and pistons. The lower one allows you to check or replace the brushes and diagnose the power unit.

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When starting to inspect a punch, they usually start with the power cord and plug. To begin with, it is enough to examine it. For a more accurate diagnosis, use an automotive or household ammeter or multimeter.

If a fault is identified in the cord, it is replaced entirely by picking up or buying a new one, with a wiring cross-section corresponding to the power consumption of the device.

If it was found that the cord is not damaged, proceed to diagnostics of the internal structure of the instrument. The main malfunctions of a punching tool are divided into:

  • failures in mechanical assemblies and components;
  • failures in the electro-dynamic “stuffing”.

Important. Before opening the device case with your own hands, it is recommended to prepare in advance the workplace and the necessary tools for diagnostics and repair. screwdrivers or a multifunctional electric screwdriver, wire cutters and pliers, a rubber hammer, a vice and wrenches for different diameters of nuts, a magnet, a set for cleaning and lubrication.

Disassembly and assembly procedure

Having freed and cleaned in the workshop a place for repair work with electrical equipment, and having prepared the necessary set of tools, the puncher begins to be sequentially disassembled to determine the malfunction, carefully examining each assembly and detail. The tool is disassembled according to the following scheme.

How to replace the cartridge

In most cases, the cartridge can be repaired. If the wear of individual parts has exceeded the permissible limits or the rubber boot and plastic skirt are damaged, it is more advisable to replace the entire chuck.

The procedure for replacing the cartridge is clear from the above procedure for disassembling the punch.

The hammer drill gets very hot

If the rock drill becomes excessively hot during operation, this is a clear sign of a malfunction of the electric motor. First of all, to prevent overheating, it is necessary to observe the operating mode of the device:

  • pause at regular intervals;
  • after exertion, allow the tool to idle.

When drilling, it is recommended to use a periodic mode: apply maximum power for no more than 1 minute, then turn on idle for 3-4 seconds.

If the temperature of the case does not decrease, then you need to revise the electric motor. Having felt the characteristic smell from under the casing of the tool, you must immediately stop working and disconnect the device from the network. You can disassemble it only after it has completely cooled down.

Replacing the main components of the punch

Replacement of key elements is best done before the part becomes unusable. This protects the instrument from more severe damage, which is more expensive and time-consuming to fix. Most often you have to replace:

  • bearings;
  • start buttons;
  • brushes;
  • patron.

How to check the start button and brushes

The rear cover must be removed to access the collector brushes and the start control button. For this, two or three screws are unscrewed from the plastic case (depending on the model).

If the cause of the malfunction lies in the wear of the brushes, you can eliminate it by installing a new pair. The working length of the brush must be at least 8 mm. Rubbing surface. no traces of scale or chips.

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The start button is checked with a multimeter. It must be remembered that the engine speed control system is also located inside the trigger mechanism. If melted plastic is visible on the button body, it should be replaced entirely, since it will no longer function properly.

Attention! It is strictly forbidden to check the operation of the button when the instrument is connected to the network.!

After replacing the button, you need to reinstall the housing cover, do not forget to tighten the screws securely. Only then can the operation of the punch be checked.

hammer, stopped, drilling, reason

Disassembly and assembly procedure

You should start disassembling yourself only if you have the appropriate tools and equipment. To repair a punch with your own hands you will need:

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  • screwdrivers with different slots;
  • vice;
  • wrenches and socket (hex) wrenches;
  • bearing pullers.

In addition, you will need spare parts for replacement, rubber seals and gaskets. To lubricate the gears of mechanisms you will need:

  • grease;
  • rags;
  • cleaning solvent.

In case of self-repair of the electric motor, in addition to the multimeter, you will need:

  • spare carbon (or graphite) brushes;
  • copper wire of the required section;
  • rewind template.

Removing the mode switch

To remove the mode switch, you must:

  • Move the toggle switch to the “strike” position (the hammer icon) and turn it about 1 cm below.
  • Free the lever from the socket.
  • Pull the lever towards you.

How to disassemble and check the gearbox: how to remove the plastic case, take out the “drunk bearing” and other elements

In order to determine the malfunction of the gearbox, it must be completely disassembled. For this, the plastic housing is removed, the gearbox is thoroughly cleaned of old grease. Disconnect from the gearbox housing:

  • floating bearing;
  • drive gear shaft;
  • raster sleeve;
  • sleeve with piston.

The floating bearing, also referred to as “drunken bearing”, is attached to the aluminum gear housing with a bracket that must be squeezed out with a flat screwdriver. The released bearing is removed and replaced if necessary. In addition, you should pay attention to the fact that inside the “drunken bearing” there is a needle bearing on which the drive gear rotates. When the hammer drill operates in the impact mode, it experiences heavy loads, and therefore often fails. A new bearing is purchased separately or assembled with an overhead shaft.

The grid sleeve contains an impact bolt that is secured internally with a metal retaining ring. On the sides of the sleeve there are two technological holes through which the locking mechanism is accessed. After releasing the ring fixing, the impact bolt freely falls out of the bushing. Inside it is directly a striker made of high-alloy steel.

When repairing or replacing the impact bolt, it is also necessary to replace the sealing rubber bushings, which ensure the tightness of the mechanism. All parts of the striker are subject to abundant lubrication with special grease.

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There is another needle bearing in the plastic casing of the gearbox at the outlet of the hub bushing, which must be well lubricated.

Does not hammer puncher

Does not spin or drill

Violation of the rotation of the drive shaft occurs either due to a breakdown in the gearbox, or if something is lost in the engine itself. It can be determined by ear.

When the motor is running and its buzz is heard, it means that the gearbox does not transmit rotation to the chuck. If, after starting the tool, the motor does not hum. the power supply is interrupted. Perhaps the circuit is broken somewhere or the coils on the coils have shorted.

What to do if it doesn’t twist under load:

Does not hold a cartridge

If the raster sleeve stops holding the chuck while the hammer is in operation, the cause is most likely in the retaining ring. It can open or become unusable due to intense load. it is replaced with pliers and a screwdriver.

The hammer drill stopped drilling, but hollows

The main reasons for which a hammer drill hammers, but does not drill, are:

  • the force of the conical spring that presses the clutch has weakened;
  • the locking roller does not fix the large gear of the barrel shaft;
  • does not hold the tool locking mechanism in the barrel;
  • The hammer drill does not hammer or drill.

The main reasons why the hammer drill does not hammer or drill are:

  • sheared teeth on the small rotor gear or on the large countershaft gear;
  • the electric motor of the perforator does not work;
  • no power to the hammer drill motor.

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Mechanical malfunctions of the Bosch rotary hammer

When mechanical malfunctions appear in the operation of the instrument, an extraneous unpleasant sound appears, sparking increases in the collector area, a burning smell appears, the instrument heats up unnecessarily, its power decreases depending on the duration of work and the effect on the material.

We will consider all the malfunctions on the Bosch 2-26 perforator diagram. Other models, such as Bosch 2-20, 2-24, differ in the design of the intermediate shaft, the installation of various drunk bearings.

The instrument gets very hot

This happens when the tool is used intensively. It is recommended to take breaks from work and de-energize the rock drill, and then let the engine idle.

If the “sparing” mode of operation does not help, the tool is disassembled and with the help of a multimeter, possible malfunctions in the engine are diagnosed.