Repair And Lubrication Of A Trimmer Gear

With frequent, intensive use of lawn mowers, the gearbox may start to warm up or make sounds uncharacteristic for its normal operation, for example, rattle. This indicates that the mechanism must be lubricated. If this is not done on time, more serious problems will arise (for example, gears will quickly wear out and need to be replaced), up to jamming. With the transmission mechanism, other failures also occur. Repair and lubrication of the gearbox can be done independently. for this you just need to get acquainted with the features of these works and stock up on some available tools.

Trimmer gear device

A trimmer reducer is a unit that transmits the rotational movement of the motor shaft to a knife or fishing line. It is located on the lower end of the bar. The transmission unit is also designed to reduce the trimmer engine speed.

The mechanism depends on the model of lawn mowers from several gears rotating at high speed. As a result, they heat up due to strong friction. If there is insufficient lubricant, or there is none at all, the process leads to severe overheating and failure of parts, and, accordingly, the need for complex repairs. To avoid this, lubricate the transmission unit in time. The disassembled gearbox is shown in the photo below.

Repair And Lubrication Of A Trimmer Gear

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

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

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

  • conical;
  • worm gears;
  • spyroid;
  • cylindrical;
  • planetary;
  • wave;
  • combined.

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

The main malfunctions of the gearbox and their solutions

With the gearbox of an electric or gas trimmer, various failures occur. The most common of them are presented in the table below. There you can find the causes of their occurrence and methods of elimination.

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Bearings are destroyed due to the use of improper grease or due to its absence. They also cause damage. severe operating conditions lawn mowing and ingress of foreign material particles (for example, broken metal teeth of mechanical gears) due to the fact that the integrity of the anthers is impaired.

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

If the knife stops rotating under load or even stands still, then this is accompanied by an uncharacteristic sound.

Most gearbox problems can be easily fixed by yourself. Replaceable parts are recommended to be purchased "native", designed for the model used lawn mowers.

Grease trimmer gear

Gear lubrication must be carried out regularly in accordance with the recommendations set out in operational instructions used model. This should also be done if:

  • new gears were installed;
  • atypical sounds emanate from the gear during the operation of the trimmer;
  • knives rotate heavily.

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

With constant use of the trimmer, its transmission mechanism is stressed by grass, dirt or sticking to the knives due to a change in torque. The lubricant must be selected high-quality to extend the life of the gearbox.

Used greases

When choosing a lubricant, the following factors must be considered:

  • the degree of adhesion of the composition to the metal node;
  • product brand;
  • lubricant consumption by gear.

Video: Repair And Lubrication Of A Trimmer Gear


Well-known manufacturers, for example, Stihl, Husqvarna and others, except for trimmers, release grease to them. Such products not only reduce wear, but also protect the metal of the gears from corrosion. Therefore, for lawn mowing from these brands, it is better to use their own lubricant products.

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

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Different models use different lubricants. This is largely determined by the intensity of use of the lawn mowers and the heating of the transmission mechanism. It is believed that there is enough lubricant if the gearbox temperature 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 gear improves;
  • lithium, which are also an excellent anti-corrosion composition, saturated with additives that increase the wear resistance of the metal without harmful substances;
  • universal, highly refined mineral oils and performance enhancing components.

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 outlets.

Champion EP-0 greasing universal 120 gr

Gear lubrication algorithm

To lubricate the gear mechanism, its preliminary disassembly is not needed. A special hole has already been laid in the device for these purposes (it is shown in the photo below). In addition to gears during lubrication, attention must be paid to such elements of the mechanism:

  • bearing unit;
  • flywheel and starter coil dog.

Grease hole

Fill with oil or apply solid lubricant through grease fitting closed with a screw. In this case, perform actions in the following sequence:

  • the gear case is cleaned of dirt and adhering grass, the area around the plug is carefully carefully so that debris does not get inside the mechanism;
  • using the appropriate tool (often it comes with a trimmer), unscrew the cork;
  • the selected lubricant is introduced into the open technological hole from the tube, or using a syringe, as shown in the photograph below;
  • screw the cork into place.

Gear lubrication

When applying grease, 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 is conveniently lubricated with solid formulations.

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The entire gearbox lubrication process is demonstrated in the video:

It is required to lubricate the transmission unit at least once during the year, but it is recommended to do this every 20 hours of intensive use of the lawn mowers. If the first signs of malfunctions with the mechanism appear, then lubricant must be added as quickly as possible.

How to replace the trimmer gear: action algorithm

To replace the gearbox with a similar part from the same manufacturer, it must first be disassembled and removed from the rod. They act in accordance with the following algorithm:

  • loosen the coupling bolts located under the gear;
  • using pliers, remove two corkscrew rings;
  • applying a puller, pull bearings from the driven and drive shafts;
  • then assemble the mechanism, installing all the spare parts in reverse order.

The disassembled gear is shown in the photo below.

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

Assembling the transfer unit is easier than disassembling it. It may only be necessary to lightly tap the hammer to fit the parts into place. After assembly, be sure to check that the driven shaft is rotated by hand.

When there is a need to replace the transmission unit with a non-original part, then you should consider their interchangeability. It should be borne in mind:

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

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

Timely lubrication of the gearbox will ensure its continued operation without repairs. In addition, modern materials well protect the metal from corrosion, increase its wear resistance. The preference when choosing should be given to the lubricant recommended by the manufacturer of the operated trimmer. If it is not possible to acquire such compositions, then the considered ones or other suitable analogous 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.