How To Find Faults And Repair A Makita Grinder With Your Own Hands

2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54

• Design features of the Makita grinder
• Tool required for repair
• Possible electrical faults
• How to troubleshoot Makita grinder control circuits
• Checking the electric motor
• How to repair the stator of a Makita grinder
• How to repair a Makita grinder rotor
• Mechanical damage
• How to repair a grinder gearbox
• Assembling grinder Makita 9565
• Spindle assembly
• Installing the rotor in the gear housing
• A few words about fakes
• Makita grinder repair video
• OVERVIEW OF MAKITA GA5030 angle grinder (makita angle grinder)
• Repair Grinder Makita GA 9020
• DIY Makita LBM repair.
• Makita 9565CV grinder repair
• BULGARKA MAKITA GA9020S OVERVIEW …
• Repair of the Chinese grinder Makita GA9020
• Repair Makita 5030 (Bulgarian 125)
• Makita 9565 CVR (Bulgarian 125)

The famous Japanese brand Makita enjoys well-deserved popularity among consumers around the world. All products of the Makita brand are distinguished by high quality, ergonomics, and affordable prices. A competent Russian consumer tries to squeeze out more from the tool than it can give. Makita angle grinders have their ultimate strength.

Do-it-yourself repair of a Makita grinder is not particularly difficult and can be performed both in a service center and on your own, since you can freely purchase the necessary spare parts. The malfunctions of the grinder and how to fix them are discussed in detail in the attached instructions.

Design features of the Makita grinder

The grinder is an angle grinder, which received this name only in the vastness of the former USSR. Structurally, any angle grinder (angle grinder) has the same structure.

The principle of operation of Makita grinders is based on the conversion of electrical energy into mechanical energy. This leads to the rotation of the shaft, on which the disc is installed for cutting, grinding, polishing. And it is called angular for the reason that in the gearbox used, the torque is transmitted at an angle of 90º.

Since the cooling of the electric motor in Makita grinders is provided by sucking in external air through the ventilation holes, the working parts of Makita grinders are covered with a special protective powder varnish that prevents dust from settling. Structurally, Makita grinders have a labyrinth system of seals and a pressurized "Start" button.

But each company introduces its own zest to attract a buyer. The Makita grinder is not deprived of this either. Makita grinders are conventionally divided into powerful and small.

Makita grinders are marked depending on the power of the electric motor.

The design features of Makita angle grinders include:

• The presence of a labyrinth device that protects the bearings from dirt and dust.
• The electric motor windings in high-power grinders are protected by an armored coating.
• Makita angle grinders are equipped with a special system that protects the tool from jerking during start-up, called the Super-Joint-System.

A few words about the SJS system. The system prevents kickback, excludes jerking and jamming of the working body, protects the electric motor from overloads.

The system uses a spring, the purpose of which is to transfer the forces from the rotor to the gears of the gearbox. The spring acts as a buffer, prevents jerks when starting and stopping. This design significantly reduces vibration and ensures smooth operation of the Makita angle grinder

Makita grinders are divided into classes according to the size of the working disc width. The grinders are conventionally divided into three classes: light, medium, heavy. In turn, each class is divided into grinders for professionals and for household needs. The professional models of Makita grinders have an increased power reserve, an integrated safety system, and an increased working resource. Professional grinders can withstand heavy loads for a long time.

Household angle grinders Makita have high performance, but very affordable prices. For Makita grinders, a disc with a maximum diameter of 230 mm can be used.

Depending on the diameter of the disc, Makita lugs are divided into classes:

• Diameter 115-125 mm characterizes the light class. Easy to hold with one hand for the body, which acts as a handle. But professional grinders of this class can be equipped with a rear handle, which has a built-in button for turning on the tool;
• Diameter 150-180 mm refers the Makita grinder to the middle class. This category includes professional and amateur models equipped with electric motors of various capacities. Modern models have a swivel rear handle;
• Diameter 230 mm characterizes heavy class grinders. In this class, Makita grinders are produced exclusively for professionals. These machines are designed to work on concrete, stones, bricks, etc. All modern consumer protection systems from injuries are incorporated in their design.

Makita grinder models are available for discs with diameters of 115 mm, 125 mm, 150 mm, 180 mm and 230 m.

In high-power grinders, carbon brushes can be replaced without removing the stator housing cover.

Makita grinders of different power differ in appearance. Professional grinders with power over 1000 W have a large body and a comfortable back handle. The handle is equipped with protective anti-vibration pads in black. Grinders with power up to 1000 W have a convenient body, which serves as a handle.

The Makita grinders have a quick-detachable cover. This design allows the protective cover to be quickly removed.

Tool required for repair

DIY repair of Makita angle grinders requires the use of a specific tool. You can't do without a set of screwdrivers. It is preferable that they be equipped with a ratchet mechanism. The best option is to use a cordless screwdriver. To repair the electrical part of the Makita grinder, you will need a tester, a device for determining the short-circuited turns of the IK-2. And also prepare an open-end wrench, bearing pullers, a hammer, and a soft metal adapter. Well, you can't do without the necessary lubricant, cleaning materials, liquids for washing off old grease.

It is necessary to start repairing the LBM with your own hands by preparing the workplace, installing the correct lighting. You will need a diagram of an angle grinder of the required model and the proposed instruction.

Any malfunction of power tools is divided into two types: electrical and mechanical.

We will consider the repair of the Makita grinder units using the example of the Makita 9565 grinder diagram.

Possible electrical faults

Electrical faults of the Makita grinder can be divided into control circuit faults, rotor failure and stator failure.

How to troubleshoot Makita grinder control circuits

If your Makita grinder won't turn on, the biggest cause may be a breakdown in the power and control circuits.

To get to the components of the control circuits, it is necessary to remove the back cover of the case, pos. 38, by unscrewing the self-tapping screw 4 × 18, pos. 39. Switch ST115-40 K9565, pos.28, is mounted in the holder of the switch, pos.27. The holder of the switch is closed by a cover, pos. 29, which is attached to the motor housing, pos. 33.

The power cable pos. 37 is suitable for the switch. Using a tester, check the continuity of the circuits from the contact of the plug to the terminals of the switch. The switch, pos. 28, is controlled by the lever, pos. 30. Check the circuit from the contacts of the switch to the carbon brushes, pos. 42.

In control circuits, the carbon brushes are the weakest link. The Makita 9565 grinder uses CB-318 carbon brushes with auto shut-off, so check the brushes.

In professional grinders, speed regulators are installed. In Makita grinders with a power of more than 1000 W, the installation of a soft start system is provided. Such a system is equipped with a Makita 9077SF lug.

If the breaker fails, the malfunction is eliminated by its complete replacement. If the power supply wire breaks or breaks, the malfunction is eliminated by replacing the whole wire or removing damaged parts of it.

The activation process is carried out using the lever pos.30. If you disassembled the grinder body for repair or maintenance, lubricate the grooves of the lever movement with silicone grease before assembly.

Checking the electric motor

In addition to control circuits, the grinder's electrical circuit includes a rotor and a stator. These are complex units, which are recommended to be repaired in specialized centers. But there is nothing inaccessible for Russian craftsmen. We recommend our own methods of repairing a stator or rotor with our own hands.

How to repair the stator of a Makita grinder

The breakdown of the stator position 24 of the grinder is indicated by the appearance of a burning smell, overheating of the grinder body, spontaneous set of revolutions of the grinder. In the grinder body, pos. 33, the stator is fastened with four self-tapping screws 4 × 70 pos. 21. To prevent damage, the stator is covered with a protection pos. 20.

Repair of the stator of the Makita grinder consists in determining a short circuit or a break in the windings. It is best to diagnose the stator with a special device called IK-2. The stator is considered defective if traces of darkening of the winding are visible, an open or short circuit of the winding turns is determined.

The stator is easy to repair. It is necessary to rewind its windings.

How to repair a Makita grinder rotor

When the grinder overheats, a burning smell appears, and sparks increase in the collector area, attention should be paid to the integrity of the rotor, pos. 13.

Dismantling the rotor is associated with a sequential disassembly. To remove the rotor, it must be freed from the gearbox pos. 3. To do this, unscrew the M6 hex nut pos. 4. To unscrew the nut, clamp the rotor with one hand. With the other hand, using an open-end wrench, unscrew the nut counterclockwise.

Remove the nut, pull out the flat washer, pos. 5, remove the bevel spiral gear, pos. 6, remove the locking spring, pos. 7. Swinging the rotor to the sides, carefully pull it out of the gearbox housing pos. 3. Having removed the circlip pos. 8, using a puller, pull off the bearing pos. 9.

The Makita 9565 grinder uses the 6001LLB bearing.

It remains to remove the flat washer, pos. 10, and the gear cover, pos. 11.

Before you is the appearance of the rotor of a Makita 9565 grinder with an insulating washer put on, pos. 14, a flat washer 7, pos. 15, a bearing, pos. 16, and a rubber boot, 22, pos. 17. In the grinder, the 627zz bearing is used on the collector side. Russian analogue 80027.

Rotor repair consists in replacing it with a new or repaired one. You can repair the rotor yourself, but you need not only patience, equipment, material. This is a high-class type of work.

Mechanical damage

In addition to the electrical part, the grinder also includes a mechanical part, the main unit of which is a gearbox.

How to repair a grinder gearbox

The reducer consists of a housing, a driving and driven gears. The pinion gear is fitted onto the rotor shaft. The driven gear is attached to the spindle pos. 50.

On the Makita 9565 grinder, the driven gear is pressed onto the spindle. And in the Makita 9558HN grinder model, the driven gear is attached to the shaft using a keyway.

Gearbox malfunctions are associated with the failure of the gear teeth. Gears are licked or some of the teeth are chipped off.

Repair of the Makita grinder gearbox consists in replacing a pair of helical gears. Replacement of gears is made only in pairs.

To remove the driven gear, you cannot do without a press or a special puller. Do not use a hammer as the gear housing is made of fragile material.

Assembling grinder Makita 9565

Before assembling a Makita grinder, check the integrity of all parts, their cleanliness. The assembly begins with the installation of the bearing and the driven gear on the spindle.

Spindle assembly

On the spindle of pos. 50, a boot of pos. 51 is put on, the cover of the body of pos. 53, the bearing housing of pos. 54. Insert pre-lubricated bearing 6201LLB into the bearing housing. Press on the driven gear, pos. 56. on the spindle. The spindle is assembled.

Installing the rotor in the gear housing

The repaired or new rotor with the bearings put on is inserted into the gearbox housing, put on, according to the drawing, all the parts, put on the drive gear and fix it with a nut.

In the process of installing the rotor in the gear housing, check the pressing of the bearing. A correctly installed rotor turns easily in the gear housing.

Installing the rotor into the stator housing

An assembled gearbox with a rotor is inserted into the stator housing, onto which a bearing

from the collector side is pressed, closed with a protective rubber boot, and the ease of rotation is checked. It remains to install the assembled spindle into the gearbox housing.

Insert the assembled spindle into the gearbox housing, pos. 3, after laying the rubber ring, pos. 55, and lubricating the bolts, pos. 52, with sealant.

Maintenance of Makita GA 5030 / Chinim Makita 5030

Video:

All operations on the assembly of the mechanical part of the grinder are accompanied by the obligatory lubrication of the parts. Pay special attention to the process of applying grease to the grinder gearbox.

Here, not only its quality is important, but also quantity. The grease in the amount of 1/3 of the gearbox volume is placed in the gearbox housing of the grinder.

After assembling the mechanical part of the grinder, each time before tightening the mounting screws, check the ease of rotation of the gearbox by turning it by the spindle.

At the final stage, it remains to install the carbon brushes, put on the back cover of the case and check the performance of the tool.

The Makita 9565 grinders are equipped with CB-325 carbon brushes. Replacing carbon brushes in a timely manner will not only preserve the rotor, but also extend the life of the entire tool.

Typically carbon brushes are replaced after 7000 hours of operation or when worn up to 8 mm in length. For

emergencies, you can use homemade carbon brushes. But at the first opportunity it is necessary to establish relatives.

If your grinder after assembly works without extraneous noise, without jerking, you can be congratulated. The task of repairing the Makita grinder is completed.

A few words about fakes

In the Russian market of the tool, fakes of Makita grinders are often found. The popular and well-promoted brand is popular not only among users, but also among various types of crooks.

Most often, powerful grinders from Makita are faked. For example, Makita 9069.

When choosing a Makita grinder, pay attention to the following details:

quality of molded plastic parts;

workmanship of the additional handle;

the low price should alert you;

carefully study the plate, you can find a lot of inaccuracies on it;

a serial number must be present on Makita grinders;

on the bodies of Makita grinders there is a mandatory inscription, which you will not find on fakes;

the carbon brushes of the original Makita have serial numbers;

as a rule, hex screws are used in the assembly, Phillips screws on fakes;

the armature and stator windings of fakes are covered with artisanal varnish.

By being careful when choosing a Makita grinder, you will not run into a fake and buy a real Japanese tool.

I wish you success!

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