Complete disassembly of the brushcutter gearbox to remove wear and grease

How to lubricate the repair of the motokosa gear reducer? Whatever the brand of motokosa, the second most important component after the engine is the gearbox, which consists of two helical gears, the smaller of which is the drive gear, the larger one is the driven gear.

Gearbox and lubrication

A gearing rotating in bearings is located in a housing consisting of two symmetrical halves, and pulled together by bolts. The drive gear receives rotation from the engine along the rod, which ends with slots (usually 7 or 9), the driven gear transmits the rotation to the spindle, which serves to attach the working body - a drum with fishing line, cables or a cutting disc.
The gear bearings on the spindle side are sealed with an oil seal that protects the bearings and lubrication in them from contamination. To replenish it, a bolt is provided on the housing, by unscrewing which you can add grease during the operation of the tool.
Regular lubrication of the gears of the motokosa gear reducer is so important that you should talk about this separately. If you exclude work with the cutting disc when it clings to a stone or curb and sends an oncoming shock pulse to the gearbox, which leads to a breakage of the tooth of the driven gear, parts of which gradually spoil the entire engagement, lubrication can delay the repair of this important unit and extend the service life by several time.

Dismantling the gearbox for checking and replacing grease and wear particles

To do this, disconnect the casing and the rod with the shaft inside from the gearbox. We remove the working body from the spindle and wash the gear assembly to make it easier to disassemble it.
We unscrew the screw plug, but it can be left in place, because it does not carry any power load.
Then we remove the drive gear from the housing. To do this, using a special puller, remove the retaining ring from the annular slot, which holds the drive gear block in the right position in the housing.
Since bearings with their outer ring are mounted in interference seats, removing them is not easy. To facilitate this task, we heat the gear housing in the bearing area with a construction hairdryer.
As soon as the metal of the body heats up, it expands and the interference disappears. Now you can easily remove from the housing the block of the helical gear with two identical twin bearings.
We proceed to extract the driven gear unit with the spindle from the gear housing. Here, first we remove the centering sleeve with pliers with narrow lips, then the gland, prying it with a screwdriver or some other suitable tool.
Also, as in the first case, we pull out the holding part, squeezing it with a snap ring puller, using the holes in the lock for this.
We heat the gearbox with a hairdryer in the area of ​​the bearings of the driven gear unit and after a while we pull it out by slightly pulling the spindle.

In custody…

After making sure that the gears, bearings, circlips and oil seal are in order, you can proceed to complete flushing and re-lubrication of the gearbox. If damaged parts are found, they must be replaced with similar ones.
Note how many wear products are on the sides of the head housing.