How to disassemble the gearbox on a brushcutter. Gearbox Repair

Disassembling the Gearbox of a Lawnmower

Owners of trimmers, mainly beginners, get confused, bordering on panic, when there is a need to change the cutting tool or line for the trimmer in the reel. Very often when trying to unscrew the mowing head, users simply cause it to fail, unaware that it unscrews in the opposite direction. To prevent this from happening if you need to replace the tool, it is recommended that you read the step-by-step instructions below.

  • Before inserting the line into the spool, turn off the brushcutter engine or disconnect the electric grass trimmer from the mains to avoid injuries caused by unintentional start-up of the cutting attachment.
  • Unscrew the accessory mounted on the gearbox shaft. To do this, the shaft must be secured by aligning the holes in the washer and axle and inserting a metal rod or screwdriver into them.
  • Unscrew mowing head. You should know that the thread on the shaft is left-handed. That’s why you have to turn the brushcutter reel clockwise to the right.
  • Disassemble the brushcutter head. The head cover is most often clamped in place. To remove it you need to push these catches into the body by pushing off the edges of the cover. In the case if your trimmer has a semi-automatic mowing head, which has a button at the bottom, then the disassembly of the nozzle must be carried out carefully, because you can lose the spring, which sometimes flies out when you remove the cover.
  • Cut the necessary amount of fishing line. It is usually 5 meters long. Use the cord of the same diameter as shown in the instruction manual of the tool. It is not recommended to exceed the maximum diameter of the line, as this will result in increased load on the engine and higher gasoline consumption.
  • Find the center of the cord by folding it in half. You’ll have a loop.
  • There are special grooves (there may be holes) inside the coil. Insert the line loop into this groove.
  • Wind the line for the trimmer on the reel, turning it counterclockwise. Make sure the line is wound as evenly as possible, with no overlap and good tension. When you have finished winding it, leave about 20cm of free fishing line and secure it into the slots on the reel flange.
  • Reassemble the mowing head. Before finally assembling the nozzle, don’t forget to insert the spring and washer (if present). Install the spool in the body, and put the ends of the cord through the holes or eyelets.
  • Put on the cover and fasten it with the clips.
  • Screw the nozzle back onto the gearbox shaft, also securing it with a screwdriver. Screw the grass trimmer spool will need to be screwed to the left (against the h. arrows).

How to replace the gear: an algorithm of actions

To replace the transmission with a similar part from the same manufacturer, it must first be disassembled and removed from the linkage. They work according to the following algorithm:

  • Loosen the clutch bolts located under the gearbox;
  • Use pliers to remove the two corkscrew rings;
  • Use a puller to remove the bearings from the driveshaft and driveshaft;
  • Then reassemble the mechanism by installing all parts in reverse order.

The disassembled gearbox is shown in the photo below.

If you do not have a camera at hand, you can try to knock down the bearings. When they are stuck and won’t move at all, you can heat them with an industrial hair dryer (at 600°C) and remove them.

It’s easier to assemble a transmission than to disassemble it. You may only need to tap lightly with a hammer to get the parts in place. After assembly, make sure that the hand shaft is driven.

When it becomes necessary to replace the transmission unit with a non-original part, we consider their interchangeability. Remember:

  • Diameter of the rod (this parameter is often 25.4 or 26 mm);
  • Drive shaft parameters. the shape of the joint and the diameter (its total value. 8mm);
  • Ability to provide protection.

If the parameters considered match, it will be possible to install the part from other models.

Timely gearbox lubrication ensures trouble-free operation without repair. In addition, modern materials protect the metal against corrosion and increase wear resistance. Preference should be given to the oil recommended by the grass trimmer manufacturer during operation. If it is not possible to purchase such compounds, then you should use the reviewed or other appropriate similar properties. When it is necessary to disassemble the mechanism during repair, it should be done carefully so as not to damage individual parts.

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The gearbox for the grass trimmer is designed to transmit torque between the shafts of the tool, located at different angles. In good condition, the unit works quietly, but when the elements wear out, it starts to make noise and overheat. Prolonged use of such a machine leads to the complete destruction of the gears and housing.

How to Disassemble the Gearbox on a Trimmer

It is believed that there is no universal lubricant for the grass trimmer gearbox, but this is not entirely true. In fact, the appropriate lubricant will be the one in which the following components are found:

From time to time, in the midst of intensive mowing work, your grass trimmer begins to make nasty, grinding noises. The gearbox. the most heavily loaded part of the appliance. is the one that complains about a lack of lubrication. And soon these “warnings” can be followed by jamming of the drive

What lubricant should be used for the gearbox of your grass trimmer?

In the course of work, the mechanical part of the grass trimmer is loaded with contact forces on teeth, reactions of resistance from grass clings (sometimes with dirt), dynamic, impact loads due to constantly changing torque. Gear lubricant for grass trimmer should fully take into account these features, so the choice of brand should be strictly individual.

The following factors are taken into account:

  • Manufacturer’s brand. Each brand is not unreasonably focused on lubricants of its own making (we can talk about cheap Chinese products later). This applies to manufacturers such as Husqvarna, STIHL, Huter, Makita and others. The exception is the trimmers for grass of domestic production: for example, Kalibr in the user manual does not indicate the brand of lubricant at all
  • Lubricant viscosity. As is known, all lubricating compositions are divided into three groups. high-viscosity (colloidal systems containing various additives), plastic compounds for universal use and solid lubricants that soften during operation.
  • Good adhesion to the surface of gearbox parts, as a result of which the grease is not squeezed out into gaps or outside the unit.
  • Lubrication intensity of a gearbox. Here we have to rely on our own experience and the recommendations of experts, because some manufacturers of trimmers, trusting in their own service centers, do not give clear recommendations on the period between two lubrication.
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How to take apart the gearbox of a brushcutter.lawnmower.gasoline trimmer

How to take apart a gearbox from a brushcutter.lawnmowers.Gasoline trimmer.

Lubricant consumption also depends on the temperature at which it retains its lubricity. When the gearbox has reached 40°C it is considered to be in a satisfactory working condition and has received enough lubricant.

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There is no universal gear lubricant for grass trimmers, but this is not entirely true. In fact, a suitable lubricant would be one that has the following components:

  • Antiwear additives that do not contain toxic lead;
  • Solid greases with the presence of graphite or molybdenum disulfide (the latter is preferable, since it retains the full lubricating power for a wide range of shaft speeds);
  • Only mineral (inorganic) greases!) oil, with a high degree of purification.

Lithium-based Gear Grease OREGON or Champion EP-0, domestic compositions Oleo-Mas, Lithol fully meet the above requirements.24, or Azmol 158, as well as those recommended by the manufacturer of a particular model of grass trimmer.

How to Grease a Grass Trimmer Gear?

There is a technological hole in the upper part of the housing, where the gear unit is mounted, which is plugged with a screw when operating the grass trimmer. This screw is unscrewed and 1.52 ml of grease is injected into the hole using the spout on the tube. If the grease was purchased in a different packaging, then for this operation will also suit an ordinary disposable medical syringe.

After that the screw is put back in its place. This procedure is worth doing every 1015 hours of operation of the grass trimmer in working mode, regardless of the user’s recommendations. Other occasions to refresh or replace the gearbox grease are when you have done minor maintenance tasks yourself (e.g. cleaning and flushing the gears before the summer season), repairing the unit, storing the grass trimmer for the winter, etc. д.

If a gear unit has been disassembled, it is advisable to completely remove all traces of previous lubricant from the surface of the parts, even if there are no signs of oxidation or contamination. And only then apply new grease. After applying lubricant it is recommended that the shaft be turned several times by hand to ensure even distribution of lubricant over all parts of the gearbox.

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Moving parts, especially gears and shafts, should be lubricated according to the rules printed in the instruction manual of the machine.

If for some reason you do not have access to this information, remember the following important rules.

  • Lubricate the structure every 8 to 10 hours of operation.
  • and more frequent lubrication is necessary when you replace the damaged gears with new ones, when you notice that the knives rotate slowly or when the gearbox makes an unusual noise during operation.
  • Choose your lubricant carefully. Many manufacturers of gardening equipment also make accessories for them, including lubricant. It is ideal to use a “normal” formula. A distinction is made between plastic, semi-liquid and solid lubricants depending on consistency. The first type is used for both toothed and screw gears, so it is considered universal. The second type is a suspension containing additives and additives. The third type in its original state is similar to the first, so carefully study the label and instructions to the lubricant.
  • To lubricate the gearbox, you do not need to disassemble it. the grass trimmer design has a special opening for this purpose. many manufacturers offer lubricant mixes in tubes with a long spout. The diameter of the lubricant inlet opening is not always the same as the diameter of this spout. This problem is easily solved by using a simple syringe, the use of which has another advantage. accurate control of the amount of grease squeezed out.
  • Grass trimmer maintenance also includes cleaning the air filter. To do this, remove the cowl, remove the part, wash it in benzene, dry it off, and clean any accumulated dirt from the seating surfaces. Then put the filter back in place and fasten the hood.

For the upper and lower gear of the lawnmower, see below.

Boom and implement drive

The pinion bar has two very important functions: firstly, it provides a rigid framework for the whole construction, and secondly, there is a shaft inside the hollow metal pinion that connects the tool with the motor. By the appearance of the boom you can determine the class of the tool, if it is curved it is convenient to work, but in this case the drive is a flexible shaft that can not transmit a lot of torque. If the rod is straight, a rigid metal rod is running through it and is much more reliable and can transmit more torque. This is why professional tools always have straight shafts.

The gears should be regularly lubricated according to the recommendations in the instruction manual of the model in use. It should also be done if:

disassemble, gearbox, brushcutter, repair

In addition to the gearbox, the grass trimmer shaft must also be regularly lubricated. This is the norm for proper maintenance of the device.

Constant use of trimmers for grass will cause its gear mechanism to suffer loads from grass clippings, dirt or due to changes in torque. Choose a quality lubricant to extend the service life of the gearbox.

Types of grease used

When choosing a lubricant, you need to consider the following factors:

Well-known manufacturers like STIHL, Husqvarna and others also make grease for their trimmers. This product not only reduces wear and tear, but also protects the gear metal from corrosion. That’s why it’s best to use lubricants for brushcutters made by these brands.

If the lubricant used has good adhesion, it hardly ever pushes out of the gearbox through the gaps.

Grease consumption varies from model to model. This is determined to a large extent by the intensity of use of the brushcutter and the heating of the gearing. It is assumed that the lubricant is sufficient if the temperature of the gearbox during operation does not exceed 40°C.

By consistency, grass trimmer lubricants can be:

In terms of composition, the following types of greases are in demand:

  • Graphite lubricants that reduce friction considerably and improve gear rotation;
  • Lithium, which are also an excellent anti-corrosion composition, saturated with additives that increase the wear resistance of metal without harmful substances;
  • Universal, high-purity mineral oils and performance-enhancing components.

Examples of suitable lubricants are: Champion EP-0, Gear Grease OREGON, Oleo-Mas, Azmol 158, Lithol.24. Also pay attention to the manufacturers’ advice on this and use the lubricant suggested by them. You can buy them at specialized retail outlets.

Champion EP-0 Universal Grease 120 gr

Algorithm of independent lubrication of the gearbox

No need to disassemble the gearing before lubricating it. The unit already has a hole for this purpose (shown in the photo below). In addition to the gears during the lubrication it is necessary to pay attention to such elements of the mechanism:

Pour oil or grease through the grease fitting with a screw. In doing so, perform actions in the following sequence:

  • Clean the gear housing from dirt and grass clings, especially the area around the plug, so that the debris does not get into the mechanism;
  • Using the appropriate tool (it often comes with the trimmer) unscrew the plug;
  • the selected lubricant is injected into the open process hole from a tube or using a syringe, as shown in the photo below
  • screw the plug into place.
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When applying grease, rotate the knife to spread it evenly over the teeth of the moving gears.

If for any reason the reducer has to be disassembled, the old lubricant material must be completely removed from all surfaces of gears and housing, shaft, and only then use the new one. It’s convenient to lubricate the disassembled mechanism with solid lubricants.

You can see the whole process in the video below:

You should lubricate the transmission unit at least once a year, but every 20 hours of heavy use should be enough. If the first signs of malfunctioning of the mechanism appear, the lubricant should be applied as soon as possible.

Lawnmower malfunctions and troubleshooting

Any type of chain saw has a hollow shaft, in which is placed a connecting cable between the motor shaft and the bottom gear, which transmits the rotation to the tool with cutting tools. carburetor and engine are located in the upper part, gearbox and working tool are in the lower part, closed by the hood. In the middle part there is a transverse handle, when the control buttons are placed. To relieve the hands, there is an unloading belt holding the boom by the operator’s torso.

When selecting a lawn mower, it is better to have a two-stroke engine than a four-stroke. Two-stroke motor is more maneuverable and easier to repair. With a four-stroke node, the vibration level is lower.

Their it follows, the lawnmower repair is to eliminate defects;

  • the engine does not start;
  • cutting mechanism does not develop;
  • engine stalls;
  • heats up the gearbox;
  • side knocking is heard; powerful boom vibration.

While troubleshooting, it is necessary to carry out diagnosis, to find a non-working node.

It is fundamental to know the lubrication points of the tool. Continuous care, cleaning the machine after work will prolong its life. Before starting work, retighten the mounting bolts, prepare the fuel, and fill the reservoir.

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How to replace the gearbox trimmer for grass: an algorithm of actions

To replace the gearbox with a similar part from the same manufacturer, it must first be disassembled and removed from the boom. Use the following algorithm to do this:

  • Loosen the tie bolts located under the transmission mechanism;
  • Using round pliers, remove the two corkscrew rings;
  • Using a puller, pull the bearings from the driven and driven shafts;
  • Then reassemble the mechanism, installing all spare parts in the reverse order.

Disassembled gear mechanism is shown in the photo below.

If there is no puller at hand, you can try to gently knock the bearings. When they stuck and do not move out of place at all, you can heat them with an industrial hair dryer (at 600 ° C) and remove the.

It is easier to assemble the gearbox than to disassemble it. Only a light tap with a hammer may be needed to set the parts in place. After assembly, be sure to check that the drive shaft rotates by hand.

When it is necessary to replace the transmission unit with a non-original part, then their interchangeability should be taken into account. At the same time it is necessary to take into account:

  • boom diameter (this parameter is often 25, mm);
  • parameters of the drive shaft. the shape of the junction and the diameter (the common value of it is 8 mm);
  • the variant of fixing the protection.

If the parameters considered coincide, it will be possible to install a part from other models.

Timely lubrication of the gearbox will ensure its long life without repairs. In addition, modern materials well protect the metal from corrosion, increasing its resistance to wear. When selecting, preference should be given to the lubricant recommended by the manufacturer of the grass trimmer in use. If such compositions are not available, you should use the reviewed or other suitable properties of analogues. When it is necessary to disassemble the mechanism during repair, it should be done carefully so as not to damage individual parts.

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Users’ reviews of lubricants

Specialists advise to use only original materials, the characteristics of which meet the requirements of the manufacturer. If there are none, you should clarify what to lubricate the trimmer gear for grass. Experienced users do not recommend the use of solidol, as this material is not suitable for the temperature and speed characteristics of the node, as well as the consistency. Also this material has no antiwear properties.

The working temperature range of solidol. from minus 40 to 65 degrees, but even at such parameters in the process of heating the density of the material increases, and the grease itself becomes coarse. If there is an urgent need to treat the tool, you can use “Lithol-24”.

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