How To Disassemble The Trimmer Gear Video

How to disassemble the grinder gearbox Preventive and repair work on the power tool should be performed carefully and accurately. With recommendations on how to disassemble the grinder’s gearbox, pull out the anchor, a list of necessary tools and other information is presented here.

We disassemble the angle grinder gearbox correctly,

There are many companies specializing in the production of angle grinders. The basic principles of the design of grinders for all firms are practically the same. However, there are some features that should be considered when repairing grinders of a certain brand. The experience of such repair is presented by masters in formats, it is presented below.


Disassembling the gearbox helped to identify the cause of the malfunction of the Fiolent grinder in the following. After carefully unscrewing the fasteners on the gearbox housing, one could see large spindle play in the support of the bearing assembly. Parts of the bearing cage confirmed the direction of repair work to replace the collapsed support assembly.

How to pull the anchor

To repair the gearbox, it is often necessary to perform its complete disassembly with release from the rotor. In some types of grinder models, this is not so easy to do. The following guidelines provide guidance on how use the inertial properties of the rotor for this purpose.

In the first, the basis for performing work is locksmith vice, and in the second from a suitable square tube a small device is made. After lightly tapping the gearbox housing against the edges of the vise or pipe, the rotor is released from the gearbox. Which method is better for the user’s choice.


The Bulgarian Sparky is the next author shows the cause of one-sided spindle rotation and a way to eliminate the defect. The collapsed rotor bearing with a support in the gearbox housing caused its distortion, which contributed to damage to the aluminum case in the form of chipped shavings. With the help of pullers and a wooden drift, the author easily copes with disassembling the gearbox and replacing both bearings on the rotor supports.

How to disassemble the grinder gearbox

The design of the grinders does not cause problems in case repair or maintenance work, related to their assembly / disassembly. This is one of the benefits of using this power tool. However, when disassembling, for example, a gearbox, work is required with great care. This is due to the materials used (aluminum, magnesium alloys, plastic), which are not very durable. Using rigid methods of working with threaded connections can compromise their integrity, which will create additional problems. Some effective methods for repairing grinders gearboxes are given in this article.

Most common malfunctions

How To Disassemble The Trimmer Gear Video

Gears set for INTERSKOL USHM-2300Wt; DWT-230 (74х15х49 teeth, 21х10х12 teeth) ACECA. 220 volt

The main reasons for the failure of grinders due to a gearbox malfunction are as follows.

  • During long-term operation, gear wear. In this case, a rustling noise appears, possibly slipping of the bevel gears relative to each other. Poor lubrication or insufficient lubrication accelerates the wear of the tapered pair.
  • Bearings also have a limited life application. If they are not replaced in a timely manner, complete destruction of the structural integrity of the bearing assembly can occur. The reason for checking it is the increased noise and vibration during the operation of the grinder, strong heating of the gearbox housing.
  • Takes place development of bearing seats. Here you can radically solve the problem by replacing the gearbox housing.
  • Not excluded the possibility of breaking the fixing elements gearbox design: nuts, screws, keys, retaining rings and other similar parts.

Breakdown prevention

To avoid breakdowns and subsequent expensive repairs, it is recommended to follow a number of simple rules for using the trimmer and servicing the gearbox.

  1. It is necessary to lubricate this garden tool immediately after purchase before using it. Usually a manufacturer (eg Interskol or Huter) applies only a small amount of lubricant, which is sufficient only for running in.
  2. At the end of the season or before long-term storage of the trimmer, disassemble the gearbox, check the condition of the bearings and gears, lubricate the assembly.
  3. Grease needs to be added after the tool has run for twenty to forty hours. With intense exercise, this time is reduced to twenty hours.
  4. It is necessary to change the lubricant to a new one when repairing the structure or before the start of the season.
  5. When the gearbox overheats or makes a lot of noise, check for grease. If it is present in sufficient quantity, it is recommended to replace it completely with another one.
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So, you can repair and lubricate the brushcutter gearbox yourself at home. Adding a lubricant is not difficult, a detailed description of this process and recommendations for choosing a suitable substance can be found in the operating instructions for the tool or on which there are many on the Internet. Most gearbox failures are typical for different brands of trimmers, it is quite easy to fix them if you know the correct procedure. And in order to avoid their appearance, it is enough to follow simple operating rules and carry out timely maintenance of the trimmer gearbox.

Gearbox lubrication algorithm

There is no need to disassemble the unit in order to lubricate the transmission mechanism of the gearbox; for this, a special hole is provided in the upper part of the housing. In addition to the gears, components such as the bearing assembly must be thoroughly lubricated. The wear of its sealed walls leads to the fact that the grease comes out of the seat and the vibration of the equipment begins. This problem is relevant for Chinese trimmers. The solution will be to replace the native bearings with high quality parts. Also, the flywheel is subject to lubrication during operation, the part is covered with fragments of grass, which create additional resistance when mowing.

Solid grease or oil is placed inside through a hole secured by a screw. In this case, the following actions are performed:

  1. The gearbox housing is carefully cleaned of dirt, especially near the plug, to prevent debris from getting inside the unit;
  2. A special device is supplied with the brushcutter, they remove the cork;
  3. From a tube or using a syringe, lubricate is introduced into the hole, smoothly turning the cutting unit so that the substance is evenly distributed over the teeth of the gears;
  4. Return the plug to its original place.

The gearbox must be lubricated annually, and with intensive use, this procedure should be performed every 20 hours of tool operation. If signs of breakage appear, the lubrication site should be treated with the composition as soon as possible.

Disassembly and replacement of the gearbox

Due to the different gear types, shape and size of the seat, gearbox interchangeability is rare. Therefore, when purchasing a new part, you should take into account the model of the old unit and the brand of the trimmer. In the event that you still need to use a non-original device, you must choose it taking into account the following nuances:

  • Rod diameter (usually 24.5 or 26 mm);
  • Seat shape and diameter (most often 8 mm);
  • Method of fixing protection.

If the listed parameters are the same, the old gear unit may be replaced with a suitable non-original part. And in order to replace it, you need to remove the gearbox from the rod and disassemble it. To do this, you will need to loosen the tie bolts located under the structure and remove a pair of corkscrews using round-nose pliers, and then remove the bearings from the driven and drive shafts using a special puller. And in order to assemble the mechanism, you need to install the removed parts in the reverse order.

Assembling the gearbox is easier than disassembling. Parts of the structure are installed in place with light hammer blows. When the device is assembled, you need to make sure that the driven shaft rotates freely if you move it by hand.

Typical malfunctions, causes and elimination

Heavy use can damage the gearbox. Most malfunctions of this unit are typical for different brands of trimmers and are eliminated in the same way.

  1. Strong heating of the transfer unit. The reasons are two new gears that are not worn in or grease: inappropriate, of poor quality, or none at all. If the problem is the lubricant, it should be replaced with another one. And new gears must be run-in for a short time without significant loads and intermittently so that the parts have time to cool down.
  2. The shaft sticks while driving, knocking and backlash appeared. These signs indicate bearing wear. It is necessary to disassemble the gearbox and install a new part. Bearing failure is caused by poor lubrication or lack of lubrication, as well as increased trimmer load or metal objects falling into its seat, which occurs due to a damaged boot. To remove and install a new bearing, you need a special puller or hammer with a block of wood. You need to beat carefully so as not to spoil the landing nest. Its preliminary heating is allowed only in the most difficult cases.
  3. When mowing, the gearbox dangles or flies off the bar. This means its case is damaged, it is necessary to install a new part. If the defects are insignificant, you can tighten the fracture with a metal clamp.
  4. If the transmission does not hold to the boom, it means the docking point is worn out. It is necessary to replace the rod with a new one or wind up the mount with electrical tape if it is partially damaged.
  5. The knife on the shaft does not rotate or stops when the load increases. The reason is wear on one of the gears or teeth. It is necessary to replace worn parts with new ones.
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The owner of the trimmer can fix most of the gearbox malfunctions on his own. You just need to have a suitable tool, spare parts (it is recommended to use original brushcutters for a particular model), and also know how to disassemble the gearbox in order to replace the damaged element with a new one.

Trimmer Reducer Lubrication and Troubleshooting

Regularly using the brushcutter, its owner may notice an increase in the temperature of the gearbox or the appearance of new uncharacteristic sounds in it, which were not heard before. These signs indicate that the mechanism requires lubrication. If you ignore them, after a while new, more significant problems will appear. So, without lubrication, gears wear out much faster and soon require replacement. In some cases, the part is jammed during operation. It should be understood that a damaged transmission mechanism can cause damage to other parts of the structure. It is quite feasible to repair the trimmer gearbox, as well as to lubricate the part with your own hands, if you know how such procedures are performed correctly, and also have the necessary tools and materials.

The device and principle of operation of the trimmer gear

A gearbox is a device for transmitting rotation to the cutting part from the motor shaft. Its second purpose is to convert the angular speed of rotation of the output shaft to lower or higher speeds.. In the first case, the device is called a demultiplier and is used on trimmers with powerful motors, in the second, the multiplier is installed on low-power tools. The gearbox is always located at the bottom of the boom of gasoline and electric streamers of different brands, be it Champion, Huter or another brand.

The gearbox device looks like this. The main parts are a pinion shaft (for transmitting motion from the motor) and a gear wheel mounted on the driven shaft (for rotating the cutting unit). To reduce the frictional force during movement, rolling bearings are placed on the bearing points of the shafts. They are protected by special washers to retain lubricant and prevent dirt from penetrating into the seat. All parts are placed in a duralumin case with a special technological hole for greasing. It is necessary so that you do not have to constantly disassemble the unit to perform lubrication.

Thus, the design of the gearbox, depending on the model and brand that produced the equipment (for example, Sterwins, Foreman), includes several gears interconnected by teeth for transmitting rotation and moving at high speed. Due to significant friction, they get very hot.

What kind of lubricant should I use for the trimmer gear?

In the process of operation, the mechanical part of the trimmer is loaded by contact forces on the teeth, resistance reactions from adhering grass (sometimes with dirt), dynamic, shock loads due to constantly changing torque. Lubrication for the trimmer gearbox must fully take into account these features, so the selection of the brand must be strictly individual.

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The following factors are taken into account:

  1. Manufacturer’s brand. Each brand reasonably focuses on its own lubricants (you can talk about cheap Chinese products later). This applies to manufacturers such as Husqvarna, Stihl, Huter, Makita, etc. The only exceptions are trimmers of domestic production: for example, the Caliber in the user manual does not indicate the brand of lubricant at all
  2. The viscosity of the lubricant. As you know, all lubricants are divided into three groups of high-viscosity (colloidal systems containing various additives), plastic compounds for universal use and solid lubricants that soften during operation.
  3. Good adhesion to the surface of gearbox parts, as a result of which the grease is not squeezed out into the gaps or out of the unit.
  4. The rate of grease consumption by the gearbox. Here you have to rely on your own experience and the recommendations of specialists, since some trimmer manufacturers, relying on their own service centers, do not give clear recommendations at all regarding the period of operation of the gearbox between two lubrications.

Lubricant consumption also depends on the temperature at which it retains its lubricity. When the gearbox is heated to 40C, it is considered that its operating conditions are satisfactory, and there is sufficient lubrication.

It is believed that there is no universal grease for the trimmer gearbox, but this is not entirely true. In fact, a suitable lubricant will be one that contains the following components:

  • Lead-free antiwear additives;
  • Solid lubricants with the presence of graphite or molybdenum disulfide (the latter is preferable, since the lubricity is fully retained for a wide range of shaft revolutions);
  • Only mineral (inorganic!) Oils, highly refined.

These requirements are fully met by Gear Grease OREGON or Champion EP-0 lithium greases, domestic compositions Oleo-Mas, Litol.24, or Azmol 158, as well as those recommended by the manufacturer of a particular trimmer model.

Lubricant for trimmer gear. How and how to lubricate?

Occasionally, in the midst of an intense mowing operation, your trimmer will make an unpleasant grinding noise. This complains about the lack of lubrication, the gearbox is the most heavily loaded unit of the device. And soon, these warnings can be followed by a jammed drive.

How to lubricate the trimmer gearbox?

In the upper part of the body, where the gear block is installed, there is a technological hole, which is plugged with a screw during trimmer operation. This screw is unscrewed, and 1.52 ml of lubricant is injected into the hole using the spout on the tube. If the lubricant was purchased in a different package, then an ordinary disposable medical syringe is also suitable for this operation.

After that, the screw is installed in its original place. This procedure, regardless of the user’s recommendations, should be performed every 1015 hours of operation of the trimmer in working mode. Other reasons for updating or replacing the gearbox lubricant are the independent performance of minor routine maintenance (for example, cleaning and flushing the gears of the gearbox before the start of the summer season), repairing the unit, preserving the trimmer for the winter, etc.

If the gear unit is disassembled, it is recommended to completely remove the remnants of the old grease from the surface of the parts, even if it does not have any traces of oxidation and contamination. And only then apply new lubricant. After applying the lubricant, it is recommended to rotate the shaft several times by hand, and make sure that the lubricant is evenly distributed over all parts of the gearbox.

When lubricating, pay particular attention to the following elements:

  1. Flywheel: as a rule, grass remnants stick to its surface intensively, and thickening grass juice creates additional resistance.
  2. Pawl of the starter coil, which, in the process of turning on the drive, constantly contacts the grooves on the flywheel. In this case, not only mechanical wear occurs, but also mechanochemical corrosion of the flywheel-dog connection, since the materials of this pair are different (the flywheel is aluminum, and the dog is steel).
  3. Bearings, if their seals are worn out, and through them, the remaining grease is squeezed out. In this case, the unit begins to vibrate intensively when loaded. This happens with Chinese-made trimmers, so in the long run it is worth thinking about replacing the bearing assembly with a better one, for example, from the Swedish company SKF.