To loosen the nut on the Husqvarna 543RS brushcutter, you must first stop the engine and let it cool completely. This nut has a left-hand thread (reverse), which means that the loosening and tightening mechanisms work differently than standard nuts.
Procedure to loosen the nut:
- Turn the nut in the direction of rotation of the cutting group. Unlike ordinary nuts, you need to turn in the same direction as the cutting head rotation, not the opposite.
- Use the socket wrench (square wrench) included in the tool kit provided with your brushcutter.
- Hold the handle of the wrench as close as possible to the guard for better control and precision.
- Apply steady and continuous force. If the nut is very tight, you can use a light penetrating oil and let it sit for a few minutes before trying again.
- Once the nut is completely loosened, you can remove the blade or cutting head for maintenance or replacement.
Tightening torque to be respected: When reassembling and tightening the nut, the tightening torque should be 35 to 50 Nm (or 3.5 to 5 kpm). Important: turn the wrench in the opposite direction to the rotation of the cutting group to tighten, again due to the left-hand thread.
Important check: After loosening, inspect the nylon block inside the locking nut. This block should not be so worn that it can be turned by hand. If the block is damaged, replace the nut to ensure safety and proper attachment of your cutting accessory.
