Why is My Roomba Side Brush Not Spinning? (SOLVED)

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Every Roomba is equipped with an edge-sweeping side brush. It is an important tool to gather dust and dirt into the robot’s suction channel. But what if the Roomba’s side brush is not spinning freely? To solve this problem, first you need to understand why it’s happening in the first place.

Why is a Roomba side brush not spinning? A Roomba side brush is not spinning because hair, dust, and dirt have accumulated underneath it. Unscrew the side brush and remove the accumulation of dust underneath. If it doesn't turn after this, the side brush module should be repaired or replaced.

In addition to dust and dirt accumulation, it may be that the side brush motor is too old, and therefore, too weak to work normally. So, before replacing your Roomba’s side brush module, take the time to learn how to fix a Roomba side brush that is not spinning. So get your Roomba ready and let’s get into it.

Why is a Roomba Side Brush Not Spinning?

There are three possible reasons why a Roomba side brush is not spinning properly. In our experience dealing with Roombas, the most obvious reason is because of hair and dust buildup underneath the side brush, especially if it’s not cleaned often. That said, here’s each possible cause explained in greater detail: 

1. The Side Brush Module is Jammed

The most common reason why a Roomba side brush is not spinning is because the side brush is jammed with hair or other contaminants. If you haven’t cleaned the side brush for so long, you’ll be surprised how much dust and dirt may have accumulated underneath it! Nine times out of ten, this is the reason.

Additionally, dust and dirt may also accumulate inside the side brush gearbox. The gearbox has spinning gears inside it, transferring power from the motor to the side brush, causing it to spin. If hair and gunk builds up inside the gearbox, the gears cannot turn properly and therefore cause the side brush to stop working.

2. Weak or Poorly-Lubricated Side Brush Motor

Another reason why a Roomba side brush is not spinning freely is because of a weak motor. Although not very common, there have been some failure reports of the side brush motor. Thankfully, iRobot will send you a warranty replacement if you contact them and explain the behavior of the side brush to them.

3. Damaged Parts

The side brush also may not work if the parts are damaged. To verify, run the Demo on your Roomba and check if the side brush motor is turning at the appropriate time. If the motor does not power up, then it might be the module failed (although it could also be a problem in the electronics connected to it).

If the motor does run, but the side brush doesn't spin, then inspect the yellow part of the side brush for cracks or excessive tears. We’ve had instances where we’ve found a small crack on the yellow part of the side brush, hindering it from spinning freely. If this is the case, it’s best to replace it with a new side brush.

Related: How to Replace a Roomba Battery PROPERLY

How to Fix a Roomba Side Brush That is Not Spinning:

If you want the quickest and easiest way to fix a Roomba side brush, without having to get your hands dirty, then just buy a new Roomba side brush module (link to Amazon). However, if you want to go the DIY route and save a little bit of money, here’s how to fix a Roomba side brush that is not spinning:

1. Clean Dust From Underneath the Side Brush 

Your first course of action is to remove all the dust accumulation from underneath the side brush. The steps to remove and replace a Roomba side brush is the same for all models. To take the side brush off of the Roomba, use a small screwdriver to remove the screw. Remove and clean the side brush and its post.

Once you have removed every dust that has settled, reinstall the side brush and check if it spins freely. If it works normally, then you’re good to go. However, if it doesn't turn after this, the side brush module should be repaired or replaced. To repair the side brush, you need to inspect the gearbox, which brings us to...

2. Clean Dirt Inside the Gearbox

To access the side brush gearbox, you first need to remove the back cover. Unscrew the side brush, then remove all the screws you see securing the back cover in place. Once the back cover is removed, you’ll notice that the side brush module is held securely in place by two screws. Unscrew them and lift the module.

Once you have the gearbox on hand, you’ll find a screw holding the cover in place. Unscrew it and lift the cover. Once you open the cover, you can see the gears inside. Remove each gear individually, then pick up any dust and hair you can find. Gunk buildup is what prevents the gears from turning properly.

After removing all the hair and dust you can find, you may also apply lubrication to the gears. This will keep it turning smoothly. We recommend using WD-40 (link to Amazon). It has a smart straw to help you accurately apply the right amount of oil, in the right place. Just be sure to not flood the gears with too much grease. 

PRO TIP: While you're addressing your Roomba, why not take the time to clean the main brush roller as well? Not only is it notorious for collecting hair and dust, but it is also known for not spinning properly if dirty. We've created an easy-to-follow guide on how to troubleshoot Roomba brush roller for beginners so be sure to read it.

3. Lubricate the Side Brush Motor Shaft

While you have access to the side brush motor, lubricate it lightly to keep it turning smoothly. Apply a little bit of oil in the small area on the motor shaft. Much to our surprise, this simple action caused the side brush to turn better, perhaps better than it ever did! Remember, a little bit of grease goes a long way.

Once you have cleaned and lubricated the entire side brush gearbox, it’s time to reassemble everything back into place. But before assembling the side brush module back into the unit, attach the side brush and try turning it by hand. If it spins freely, congratulations, your side brush is back to normal.

Side Brush Still Not Working?

If you have done the steps above and the side brush is still not working, check the wires and connector. It may be loose, damaged, corroded, or the combination of all three. If this is the case, your best bet is to buy a new side brush module. Thankfully, iRobot sells one compatible for Roomba 500, 600, 700, and 800 Series.

Buying a new side brush module is a cheap alternative to add a few years into your Roomba, especially if it’s relatively old. It is also a simple and easy solution to fix a non-spinning Roomba side brush without you having to disassemble it and get your hands dirty. We hope our guide can help you, and good luck. 🙂

Related: How to Reset a Roomba THE RIGHT WAY

Bottom Line

And there you have it, the complete troubleshooting guide to the question: why is my Roomba side brush not spinning? Nine times out of ten, the reason behind this problem is the accumulation of hair, dust, dirt, and gunk underneath the side brush. This is true for all Roomba models, old and new.

We have been fixing and “hacking” Roombas since the 400 Series and we make it a habit to remove the side brush screw each day, pull up the side brush, and remove the accumulation of dust underneath it. If you own a Roomba, taking five minutes just to keep the side brush clean will ensure it lasts a long time. 🙂

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