This seemed to solve everything until the last couple of months the robot wouldn't stop clicking and clacking. Finally it stopped running altogether - after a few seconds of running we'd get an error message and it would stop. We gave up trying to get it to work and started looking for a Roomba repair shop - to no avail. To be sure there are places on the net that, for $50 and shipping will take your robot and diagnose the issue, with no certainty of what it will cost. For a $250 item that seemed a little steep. I was thinking of buying a new unit when I said to myself, let's disassemble it and try to fix it. Worse case scenario I break it and have to buy a new one - the exact issue I was already facing.
Flip the Roomba over on its back on a stable, flat surface that you wont mind having a pile of dirt, hair and other vacuum cleaner detritus. Removing the bottom panel (4 screws and the twirly thingy have to come off) you expose the inner workings of the roomba. Remove the brushes, the brush cage (it just pulls out) and the filter holder and you can get to the brush carriage. You don't have to remove the battery.
On the sides of the brush carrier towards the filter there are two arms on each side of the carrier. Gently pry these out (I used a flat tip screw driver) - they only need to come out about an eighth of an inch to get them free. You now can pry the brush carriage free.
BE CAREFUL!! There are wires attached to the bottom of the brush carriage that don't detach (great design feature) along with a cord that pulls the assembly up into the roomba while its moving. You can get it free enough to get to the gearbox assembly on one side of the carriage. This is the side of the brush assembly that the brushes have to be inserted into.
On the outside face of the gearbox are a number of small screws that you'll need to remove. Put these in a safe spot as they're small and will roll away or get lost in all the dirt that you're about to remove from the innards of the gearbox. As you pry away the faceplate (fingernails will suffice) be very careful to not drop the gears out, or if you do pay close attention to which gear goes where. Once you've cleaned this out you'll have to replace them exactly as they're located. Be sure to note and keep the small translucent washers that are between the gears and the faceplate.Clean all the junk out, removing each gear to clean the hair and dirt that has accumulated there. Replace the gears in the right order, reattach the faceplate, reset the brush assembly into the Roomba and reattach the bottom plate.
Turn it on. If you've done everything right, the Roomba should be ready to clean up for you again!
