Roomba making a loud grinding noise
DIRECT ANSWER
COMMON CAUSES · RANKED
Hair packed in the brush end caps MOST COMMON
Hair works past the caps and felts up around the bearings — the brush fights its own mount and rattles or grinds.
Debris inside the cleaning head gearbox
Dust and hair slip through the extractor mating points straight onto the gear wheels, adding friction until the gears grind or stall.
Side brush gearbox jammed UNCOMMON
A rhythmic clicking from the corner of the robot rather than the center — hair around the side brush gear shafts.
Worn drive wheel gearbox UNCOMMON
Noise only while the robot moves, even with brushes removed, points at a wheel module.
HOW TO FIX IT
Isolate the noise
Pull the main brushes out and run the robot briefly. Noise gone means brushes or bearings; noise still there means gearbox or wheels.
Strip and clean the brushes
Pop the end caps — yellow on the 600 series — pull out the felted hair rings, and clear the square and hex drive sockets.
Open the cleaning head
Unscrew the cleaning head module and pick hair off the gear shafts. On 800 and 900 series the gearbox is a known dust trap.
Check the side brush and wheels
Remove the side brush and inspect its post, then spin both drive wheels by hand and listen for the grind.
Gears visibly chewed? Replace the module
Stripped teeth don't recover. A new cleaning head module — or fresh brushes if the wear stopped at the bearings — ends the noise.
COMPATIBLE PARTS
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Bristle and beater brush set — 600 series
Cut wrapped hair off the bristle brush weekly; replace the pair when bristles splay outward.
Check price on Amazon ↗Dual multi-surface rubber brushes — e, i & j series
iRobot suggests new rubber brushes every 6-12 months; sooner in homes with long-haired pets.
Check price on Amazon ↗Cleaning head module — 600 series
Replacing the whole module is often cheaper than chasing worn gearbox parts on error 2 repeats.
Check price on Amazon ↗Sources
Corrections
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