the brush roll on my 1785a just stopped spinning mid-use, now it makes a humming noise.

Diagnosis

The humming noise you hear is the sound of the motor continuing to run while the brush roll remains stationary. This indicates a mechanical failure in the drive system rather than an electrical failure of the motor itself. In the Bissell CrossWave 1785A, this is almost always caused by a "seized" roll, where debris—typically long hair, synthetic carpet fibers, or string—has wound around the end caps of the brush roll, creating enough friction to lock the axle completely. When the roll is locked, the motor's torque is transferred into the drive belt. If the debris is stubborn, the belt will either slip (causing the hum) or, in more severe cases, snap or stretch. To confirm this, check the end of the brush roll for "bunched" debris. If the roll is physically impossible to turn by hand, the debris has compromised the bearing or the belt has failed. If the roll spins freely by hand but won't engage when powered on, the drive belt has likely snapped or slipped off the pulley.

How to Fix It

Follow these steps to clear the jam and restore rotation:

1. Immediately disconnect the power cord from the wall outlet to prevent the motor from overheating during the repair.
2. Lay the CrossWave on its back or side on a flat surface. Locate the brush roll release mechanism on the bottom of the unit.
3. Unlock the brush roll by pressing the release tabs or removing the retaining clips (depending on your specific sub-model variation) to slide the brush roll assembly out of the housing.
4. Inspect both the left and right end caps of the brush roll. Use a pair of heavy-duty sewing scissors or a seam ripper to cut through the hair and string wrapped around the axle. Do not pull the debris outward, as this can warp the plastic end caps; cut it lengthwise and peel it away.
5. Check the "drive side" of the roll (the side with the gear/pulley). Ensure no debris is lodged between the belt and the pulley wheel.
6. Manually rotate the brush roll 360 degrees to ensure there is no remaining resistance.
7. Slide the roll back into the chassis, ensuring it clicks firmly into the drive gear. Lock the retaining clips.
8. Plug the unit in and test the brush roll on a hard surface first to verify the humming has stopped and the roll is spinning at full speed.

If That Didn't Work

• Replace the Drive Belt: If the brush roll spins freely by hand but the motor hums without moving the roll, the belt has likely snapped. You will need to disassemble the motor housing to access the belt. Inspect the belt for any fraying or a complete break. Replace it with a genuine Bissell CrossWave replacement belt, ensuring the tension is tight enough to grip the pulley.
• Inspect the Motor Brushes: If the humming is accompanied by a burning smell, the motor brushes may be worn out or the motor may have overheated and tripped an internal thermal fuse. Allow the machine to cool for 60 minutes. If it still won't spin, the motor assembly may require professional replacement.
• Clear the Intake Path: Check the suction channel directly behind the brush roll. A large object (like a coin or a pebble) can sometimes wedge itself between the roll and the housing, preventing rotation even if the roll itself is clean. Use a flashlight to inspect the throat of the vacuum.
• Check the Brush Roll End Caps: If the plastic end caps are cracked or melted from friction, the roll will wobble and jam. Replace the brush roll entirely with a new 1785A compatible roll if the plastic housing on the brush itself is deformed.

Heads Up

• Weekly Maintenance: To prevent future jams, remove the brush roll every 5-10 uses and clear the hair from the ends. This prevents the "snowball effect" where debris builds up until it locks the motor.
• Avoid High-Pile Rugs: The 1785A is designed for hard floors and low-pile area rugs. Using it on thick shag rugs increases the load on the belt, significantly increasing the risk of belt slippage or breakage.
• Dry the Roll: After cleaning the brush roll, ensure it is completely dry before reinstalling it. Moisture trapped in the end caps can lead to premature wear of the plastic bearings.
• Listen for Changes: If you notice the pitch of the motor changing or a slight "squealing" sound, stop immediately and clear the roll; this is the early warning sign that the belt is slipping.