How to disassemble the Stihl trimmer gearbox

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The trimmer gearbox is a module that is needed for torque. The device includes one or more gears that rotate at high speed. The mechanism of this equipment is called a demultiplier, since it converts the angular speed of rotation of the output shaft into its lower speed.

Manufacturers equip lawn mowers with gearboxes that convert the low angular speed of the input shaft into an output speed that is higher. The low power motor allows for the highest number of trimmer blade revolutions. The name of this option is multiplier. The petrol-powered trimmer is capable of flawlessly performing work associated with mowing lawns, removing weeds. The unit needs proper care, which involves changing lubricants.

Disassembly and replacement of the gearbox

Due to the different types of gears, the shape and size of the seat, gearbox interchangeability is rarely possible. 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);
protection fixation method.

If the listed parameters are the same, the old gear unit may be replaced with a suitable non-original part. And in order to carry out a replacement, you need to remove the gearbox from the rod and disassemble. To do this, you will need to loosen the tightening 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 to assemble the mechanism, you need to install the removed parts in the reverse order.

Advice! In the absence of a puller, the bearings can be gently knocked out with a hammer and a block of wood. The blows must be applied carefully so as not to damage the seat. However, it is impossible to crank the stuck parts, therefore, to remove them, you need to warm them up with a construction hair dryer (temperature is 600 ° C).

Assembling the gearbox is easier than disassembling. Parts of the structure are set 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.

Gearbox lubrication algorithm

There is no need to disassemble the unit to lubricate the gearbox transmission. 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. The flywheel is also subject to lubrication. during operation, the part is covered with fragments of grass, which create additional resistance when mowing.

Important! It is also necessary to lubricate the pawl of the starter coil, since when starting it touches the grooves on the flywheel. This leads to its wear and tear, as well as to the appearance of mechanochemical corrosion due to the fact that the parts are made of various materials (flywheel. aluminum, pawl. steel).

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

the gearbox housing is carefully cleaned of dirt, especially near the plug, in order to prevent debris from getting inside the unit;
a special device is supplied with the lawn mower, they remove the cork;
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;
return the plug to its original place.

Advice! If it becomes necessary to disassemble the gearbox, remove the old grease from the housing, from the surface of the shaft and gears, and then apply a new one. When disassembled, it is very convenient to lubricate parts with solids.

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 of the lubrication site as soon as possible.

How to lubricate the gearbox

Before starting the trimmer for the first time, perform a number of sequential actions:

Changing gearbox attatchments/cultivator gearbox on stihl trimmers

Inspect the gearbox.
Prepare the correct fuel mixture.

The implementation of these actions is recommended not only for new devices, but also when preparing old units for the next season after storage. If there is little or no lubricant, then this leads to increased friction of the gear part of the gearbox. Since it must operate at fairly high speeds, the gearbox must be checked regularly before starting the petrol trimmer.

If the gears overheat, this will damage the mowers’ gearbox. To prevent this, starting and running in the trimmer begin by inspecting and lubricating the bevel gear. To fill oil in the gasoline scythe gearbox before starting it, you should:

Unscrew the screw that is located at the bend of the gear housing.
Stir in the “Litol” grease in the amount of 1-2 ml.
Tighten the screw.

Grease is added to the gasoline trimmer gearbox every 8-10 hours of unit operation.

For this, a special technological hole is provided in the housing. The module should be inspected for the presence of grease both before the first and before each subsequent use of the equipment.

How to disassemble the trimmer gear

Regularly using the lawnmower, its owner may notice an increase in the temperature of the reducer 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 need to be replaced. 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.

You can purchase a special compound for the gearbox in the form of tubes with a long supply spout, the diameter of which must match the size of the hole. This is not always the case, since models from different manufacturers differ in their hole diameter.

In this case, summer residents should prefer the use of a medical syringe, which is convenient in that it allows you to accurately measure out a portion of the mixture.

Repair and lubrication of the trimmer gear

With frequent, saturated use of lawn mowers, the gearbox may begin to heat up or emit sounds unusual for its normal operation, for example, grinding. This indicates that the mechanism needs to be lubricated. Trimmers and chainsaws trimmer reducer trimmer Stihl video how to disassemble the reducer. How to properly lubricate the trimmer gear? How to disassemble the upper gear reducer. If this is not done just right, then more severe obstacles will arise (for example, gears will rapidly wear out and it will be useful to change them), right before jamming. Other breakdowns also occur with the transmission. Repair and lubrication of the gearbox can be performed without the help of others. for this you just need to familiarize yourself with the features of these works and stock up on some available tools.

Trimmer reducer device

A trimmer gear is a unit that transmits the rotational motion of the motor shaft to a knife or line. It is located at the lower end of the lawn mower bar. The transfer assembly is also designed to reduce the rpm of the trimmer motor.

The mechanism consists, depending on the lawn mower model, of several gears rotating at high speed. As a result of this, they heat up due to strong friction. If there is not enough lubricant, or there is none at all, then the process leads to severe overheating and failure of parts, and, accordingly, the need to carry out complex repairs. To prevent this from happening, the transmission unit should be lubricated in time. The disassembled gearbox is shown in the photo below.

Gearboxes of modern trimmers of different models from different manufacturers differ from each other in design and seat size. It happens:

The most common round seat diameters are 24, 25.5 and 26 mm.

lawn mowers are equipped with gearboxes with different types of gears:

conical;
worm;
spiroid;
cylindrical;
planetary;
wave;
combined.

The drive shaft and gearbox are heavily loaded trimmer assemblies that are subject to significant wear. Between them, the movement is transmitted due to the engagement of the teeth of the gears located at different angles to each other. The gear train works effectively only if there is no mechanical damage. In this case, the mechanism should not overheat, otherwise it may jam.

Types of gearboxes and lubricants

Gearbox mechanisms by type of transmission are divided into the following types:

Wave.
Cylindrical.
Planetary.
Worm.
Spiroid.
Conical.
Combined.

The main elements of cylindrical mechanisms are gear cylinders. lawn mowers are very often equipped with modules of this type, worm-type gearboxes, etc. are installed on the trimmers. Transmission to them is carried out due to the operating screw. Planetary types of gears differ in coaxial arrangement of shafts, and bevel gears. in intersecting.

The gear train is able to work effectively only if there is no mechanical damage to the unit. Normal temperature conditions must be created for the device to function properly. Even the smallest distortions or overheating can cause jamming of the mechanism elements. This can lead to a stop of the trimmer, malfunctions of the mechanism and serious consequences of its use, requiring repair of the unit parts.

Lubricants for trimmer gearboxes, the types of which depend on their consistency, allow to provide the necessary maintenance of the equipment:

Semi-liquid lubricants are characterized by the presence of a colloidal system with m of various additives and additives. The grease is suitable for both helical and gear drives and is therefore a versatile option. The initial state of solid suspensions is plastic.

Lubrication of the lawn mowers’ gearbox is provided with a special compound specifically for gearboxes. Most lubricants are in the form of semi-fluid systems. When choosing the required lubricant, it is required to take into account the temperature regime for which the mixture is intended.

Trimmer Reducer. Lubrication and Troubleshooting

Typical malfunctions. causes and elimination

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

Excessive heating of the transfer unit. There are two reasons. new gears that are not worn in or lubrication: inadequate, 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 within a short time without significant loads and intermittently so that the parts have time to cool down.
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 will 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 preheating is allowed only in the most difficult cases.
When mowing, the gearbox dangles or flies off the bar. This means that its body is damaged, it is necessary to install a new part. If the defects are insignificant, you can pull off the fracture with a metal clamp.
If the transmission does not hold to the boom, it means that 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.
The knife on the shaft does not rotate or stops when the load increases. The reason is the wear of one of the gears or teeth. It is necessary to replace worn-out parts with new ones.

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 ones. for a specific model of lawn mowers), and also know how to disassemble the gearbox in order to replace the damaged element with a new one.

Gearbox lubrication algorithm

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

the gearbox housing is carefully cleaned of dirt, especially near the plug, in order to prevent debris from getting inside the unit;
a special device is supplied with the lawn mower, they remove the cork;
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;
return the plug to its original place.

Trimmer Gear Lubrication

Gears must be lubricated regularly in accordance with the recommendations set out in the operating instructions for the model used. This should also be done if:

new gears were installed;
atypical sounds emanate from the gearbox during trimmer operation;
knives turn hard.

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

With continuous use of the trimmer, the transmission is subjected to stress from grass adhering to the blades, dirt, or due to changes in torque. The lubricant must be selected of high quality in order to extend the life of the gearbox.

Lubricant selection rules

Many garden tool companies such as Stihl and Husqvarna make their own lubricants for their products. In this case, it is recommended to use just such a product. it is the best way to reduce the wear of equipment. If original lubricant is not available for the trimmer, several factors should be taken into account when choosing a composition:

Stihl Gearbox Replacement, Lawn Care Vlog #69

the quality of the brand that produces the lubricant;
the viscosity of the composition. this parameter is influenced by the torque of the shaft;
adhesion to the surface of the assembly components;
consumption of the lubricating coating. take into account the air temperature, the type and volume of work carried out.

Advice! If it is difficult to choose a lubricant, it is better to purchase a universal composition. It usually contains a number of additional components to protect the gearbox and extend the life of the gearbox.

By consistency, lubricants can be liquid and semi-liquid, with m of various additives and additives, as well as plastic and solid. The plastic ones are the most common, and the hard ones represent their original state. The most popular in terms of composition are:

graphite lubricants that reduce friction and improve gear movement;
lithium compounds with high anti-corrosion properties and additives that reduce metal wear;
universal substances containing mineral oils and additives that increase the performance of the gearbox.

The most common lubricants include: Litol-24, Champion EP-0, Azmol 158, as well as the composition of the Stihl company.

Used types of grease

When choosing a lubricant, you must consider the following factors:

the degree of adhesion of the composition to the metal of the assembly;
product brand;
lubricant consumption by the transmission mechanism.

Well-known manufacturers, for example, Stihl, Husqvarna and others, in addition to trimmers, also produce lubricants for them. These products not only reduce wear, but also protect the gear metal from corrosion. Therefore, for lawn mowers from these brands, it is better to use their own lubricant products.

If the compound used for lubrication has good adhesion, then it is practically not squeezed out of the gearbox through the gaps.

Different models have different grease consumption. This is largely due to the intensity of use of the lawn mowers and the heating of the transmission. It is considered that the lubricant is sufficient if the temperature of the reducer during operation does not exceed 40 ° C.

By consistency, trimmer lubricants can be:

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

graphite, significantly reducing friction, as a result of which the rotation of the gears improves;
lithium, which is also an excellent anti-corrosion composition, saturated with additives that increase the wear resistance of the metal without harmful substances;
universal components containing highly refined mineral oils and improving performance characteristics.

Examples of suitable lubricants are: Champion EP-0, Gear Grease OREGON, Oleo-Mas, Azmol 158, Litol. 24. You should also pay attention to the advice of manufacturers on this issue and use the materials they offer. You can buy them at specialized retail outlets.

Champion EP-0 universal grease 120 gr

Algorithm for self-lubrication of the gearbox

For lubrication of the transmission mechanism, its preliminary disassembly is not necessary. A special hole for these purposes is already embedded in the device (it is shown in the photo below). In addition to gears, when carrying out lubrication, attention should be paid to the following elements of the mechanism:

bearing unit;
flywheel and starter coil pawl.

Grease injection hole

Fill in oil or add solid lubricant through a grease nipple closed with a screw. In this case, the actions are performed in the following sequence:

clean the gearbox housing from dirt and adhered grass, especially carefully the area around the plug so that debris does not get inside the mechanism;
using the appropriate tool (often it comes with a trimmer), unscrew the plug;
into the open technological hole, the selected lubricant is injected from a tube, or using a syringe, as shown in the photo below;
screw the plug into place.

Gear lubrication

When applying lubricant, you need to rotate the knife so that it is evenly distributed over the teeth of the moving gears.

If for any reason the gearbox needs to be disassembled, then the old lubricant must be completely removed from the entire surface of the gears and the housing, the shaft, and only then use a new one. The disassembled mechanism can be conveniently lubricated with solid compounds.

The whole gear lubrication process is demonstrated in the video:

Lubrication of the transfer unit is required at least once a year, but it is recommended to do this every 20 hours of intensive use of the lawn mower. If the first signs of malfunctions with the mechanism appear, then the lubricant must be added as soon as possible.

Trimmer reducer device

A trimmer gear is a unit that transmits the rotational motion of the motor shaft to a knife or line. It is located at the lower end of the lawn mower bar. The transfer unit is also designed to reduce the trimmer engine speed.

The mechanism consists, depending on the model of the lawn mower, of several gears rotating at high speed. As a result, they heat up due to strong friction. If there is not enough lubricant, or there is none at all, then the process leads to severe overheating and failure of parts, and, accordingly, the need to carry out complex repairs. To prevent this from happening, the transmission unit should be lubricated in time. The disassembled gearbox is shown in the photo below.

Gearboxes of modern trimmers of different models from different manufacturers differ from each other in design and seat size. It happens:

round;
in the form of an asterisk;
square.

The most common round seat diameters are 24, 25.5 and 26 mm.

lawn mowers are equipped with gearboxes with different types of gears:

conical;
worm;
spiroid;
cylindrical;
planetary;
wave;
combined.

Main gearbox malfunctions and ways to eliminate them

Various breakdowns occur with the gearbox of an electric or gasoline trimmer. The most common of them are presented in the table below. There you can also find the causes of their occurrence and methods of elimination.

Gearbox malfunction	Possible causes of breakdown	Remedy
the transfer unit is very hot	the use of an unsuitable (low-quality) lubricant or its absence	you need to replace or add lubricant
the transfer unit is very hot	the gears are new and not worn down	for running-in, run for a short time without heavy loads with regular stops so that the mechanism has time to cool down
jamming of the shaft during rotation, the appearance of backlash and knocking	destruction or significant wear of any of the bearings	replace the failed bearing with a new one
the transmission mechanism flies off the mower bar or staggers	damage to its hull	it is necessary to replace the part
	damage to its hull	in some cases, with minor damage with a clamp made of metal, the place is pulled together with a break
not fixed to the pipe	docking point wear	you can make an insulating tape rewind at the attachment point or change the bar
the output shaft with the knife does not rotate or stops in the event of an increase in the load	wear of teeth on gears or one of them	replacement of the interacting pair of worn parts is required

Bearings are destroyed due to the use of inappropriate lubricant or due to lack of it. Also, their damage is caused by harsh operating conditions of lawn mowers and the ingress of foreign particles of material (for example, broken metal teeth of mechanical transmissions) due to the fact that the integrity of the anthers is broken.

To remove the bearing, you need to disassemble the gearbox and use a special puller. If not, then you can try to do it with a hammer with a guide. In this case, work should be done carefully so as not to damage the seat. It is not recommended to use the preheating method to shoot the bearing. This is due to the fact that the metal can lose the required performance.

If the knife stops rotating under load or does not stop at all, then this is accompanied by an uncharacteristic sound.

Most gearbox problems can be easily fixed by hand. Replaceable parts are recommended to purchase “native”, intended for the model of lawn mowers.

Algorithm for self-lubrication of the gearbox

bearing unit;
flywheel and starter coil pawl.

Grease injection hole

Fill in oil or add solid lubricant through a grease nipple closed with a screw. In this case, the actions are performed in the following sequence:

clean the gearbox housing from dirt and adhered grass, especially carefully the area around the plug so that debris does not get inside the mechanism;
using the appropriate tool (often it comes with a trimmer), unscrew the plug;
into the open technological hole, the selected lubricant is injected from a tube, or using a syringe, as shown in the photo below;
screw the plug into place.

Gear lubrication

When applying lubricant, you need to rotate the knife so that it is evenly distributed over the teeth of the moving gears.

The whole gear lubrication process is demonstrated in the video:

Trimmer Gear Lubrication

Gears must be lubricated regularly in accordance with the recommendations set out in the operating instructions for the model used. This should also be done if:

new gears were installed;
atypical sounds emanate from the gearbox during trimmer operation;
knives turn hard.

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

Repair and lubrication of the trimmer gear

Used types of grease

When choosing a lubricant, you must consider the following factors:

the degree of adhesion of the composition to the metal of the assembly;
product brand;
lubricant consumption by the transmission mechanism.

If the compound used for lubrication has good adhesion, then it is practically not squeezed out of the gearbox through the gaps.

By consistency, trimmer lubricants can be:

liquid;
semi-liquid;
solid;
plastic.

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

graphite, significantly reducing friction, as a result of which the rotation of the gears improves;
lithium, which is also an excellent anti-corrosion composition, saturated with additives that increase the wear resistance of the metal without harmful substances;
universal components containing highly refined mineral oils and improving performance characteristics.

Champion EP-0 universal grease 120 gr

How to replace the trimmer gear: the algorithm of actions

To replace the gearbox with a similar part from the same manufacturer, it must first be disassembled and removed from the rod. In this case, they act according to the following algorithm:

loosen the tie bolts located under the transmission;
using round nose pliers, remove two corkscrew rings;
using a puller, pull the bearings from the driven and drive shafts;
then the mechanism is assembled, in the reverse order, installing all the parts.

Disassembled transmission mechanism is shown in the photo below.

If the puller is not at hand, then you can try to gently knock down the bearings. When they are stuck and do not budge at all, you can heat them with an industrial hair dryer (at a temperature of 600 ° C) and remove.

Assembling the transfer assembly is easier than disassembling it. You may only need to tap lightly with a hammer to set the parts in place. After assembly, it is imperative to check that the driven shaft can be rotated by hand.

When there is a need to replace the transfer unit with a non-original part, then their interchangeability should be taken into account. It should be borne in mind:

rod diameter (this parameter is often 25.4 or 26 mm);
parameters of the drive shaft. the shape of the docking place and the diameter (its common value is 8 mm);
protection fixing option.

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

Timely lubrication of the gearbox will ensure its long-term operation without repairs. In addition, modern materials protect the metal well from corrosion and increase its wear resistance. When choosing, preference should be given to the lubricant recommended by the manufacturer of the trimmer being operated. If it is not possible to acquire such compositions, then the considered or other analogs suitable in terms of properties should be used. When it is necessary to disassemble the mechanism during repairs, this should be done carefully so as not to damage individual parts.

Sources:

http://eco-podarki.ru/post/polnaya-razborka-reduktora-motokosy-dlya-udaleniya-produktov-iznosa-i-zameny-smazki.html
http://tehnika.expert/dlya-sada/trimmer/remont-i-smazka-reduktora.html

Grass Trimmer disassemble, gearbox, stihl, trimmer