my hoover pet swivel is making a loud rattling or grinding noise when i turn it on, sounds bad.

Diagnosis

The loud rattling or grinding noise in the Hoover MAXLife Pro Pet Swivel (UH74220PC) is typically caused by one of two failure points: mechanical obstruction or bearing degradation. When a foreign object—such as a small pebble, a coin, or a concentrated clump of pet hair—gets lodged between the brush roll and the plastic housing, it creates a rhythmic rattling sound as the roll rotates at high RPMs. If the noise is a high-pitched, metallic grinding, it indicates that the lubricant has failed or the plastic bushings at the ends of the brush roll have worn down, causing the metal drive shaft to rub directly against the chassis. To confirm the source, perform a "spin test." With the unit unplugged, manually rotate the brush roll. If you feel a "catch" or hear a clicking sound, you have a physical obstruction. If the roll spins freely but feels "loose" or wobbles vertically, the bearings are shot. If the noise only occurs when the motor is engaged but the roll is not spinning, the issue is likely located within the motor's internal drive belt or the impeller fan, though 90% of these cases are localized to the brush roll assembly.

How to Fix It

To resolve the noise, you must perform a deep clean of the brush roll and inspect the drive components. Follow these precise steps:

1. Unplug the vacuum from the wall outlet to ensure the motor cannot engage during the process.
2. Flip the vacuum onto its back. Locate the two release latches on the bottom plate. Press these firmly and lift the plate to expose the brush roll.
3. Use a pair of heavy-duty scissors or a seam ripper to cut through the hair and string wrapped around the brush roll. Do not pull the hair manually, as this can tug the brush roll out of alignment and damage the bearings.
4. Grasp the brush roll and pull it straight out of the housing. Inspect the left (drive) side and the right (idler) side.
5. Check the plastic end caps for cracks or missing chunks of material. If the plastic is worn through to the metal, the brush roll must be replaced.
6. Clean the drive belt area. Ensure the belt is seated correctly in the grooves of the motor pulley and is not frayed or slipping.
7. Reinsert the brush roll, ensuring it snaps firmly into the drive gear on the left side. Replace the bottom plate and lock the latches until they click.

If That Didn't Work

• Replace the Brush Roll Assembly: If the grinding persists after cleaning, the internal bushings have likely flattened. Purchase a replacement brush roll specifically for the UH74220PC model. Avoid generic "universal" rolls, as the swivel head requires a precise fit to maintain suction.
• Inspect the Drive Belt: A worn-out or stretched belt can slip against the pulley, creating a high-pitched screeching or rattling sound. If the belt shows signs of "glazing" (shiny, flat spots) or hairline cracks, replace it with a new reinforced rubber belt.
• Clear the Fan Impeller: If the noise is coming from the upper motor housing rather than the floor head, a small piece of debris (like a toothpick or pebble) may have bypassed the filter and entered the impeller fan. This requires removing the outer casing to clear the fan blades.
• Lubricate the Swivel Joint: If the rattling occurs specifically when turning the vacuum, the swivel pivot may be dry. Apply a small amount of silicone-based lubricant to the swivel joints; avoid WD-40 as it can attract more dust and grime.

Heads Up

• Avoid Overloading: Never use the vacuum to pick up large pebbles or hard plastic shards, as these can chip the brush roll bearings and lead to permanent grinding noises.
• Weekly Maintenance: To prevent bearing failure, cut hair off the brush roll every two weeks. Accumulated hair puts excessive lateral pressure on the bearings, causing them to warp.
• Filter Check: Ensure your filters are clean. A clogged filter forces the motor to work harder, increasing vibration and making any existing mechanical rattle sound significantly louder.
• Power Warning: Always ensure the unit is completely unplugged before reaching under the bottom plate; the Pro Pet series has a high-torque motor that can cause injury if accidentally triggered.