Machine is very loud or makes grinding noise during operation

Safety first: Unplug the machine. Do not continue to run it if loud grinding or screeching is heard.

• Isolate noise source: Run each function separately (brush only, vacuum only, traction only) to determine which system is noisy.
• Inspect brush area: Remove the brush and check for stones, screws, or other debris in the housing. Clean thoroughly.
• Check vacuum motor: If noise is from the vacuum motor area and accompanied by a burning smell, the motor bearings may be failing. Replace the Nilfisk vacuum motor assembly.
• Inspect gearboxes: On self‑propelled models, inspect the traction or brush gearbox for broken teeth or lack of lubrication. Replace the gearbox if damaged.