@zlarson Ah, I can answer the part about the belt tension. If you look carefully at that end cap, you'll find that the circular part that holds the roller isn't centered on the square part that fits into the head. Depending on which way you put it in, it will exert various amounts of tension on the belt, moving it closer or further away from the drive gear, thus loosening or tightening the belt. Fit it in, then rotate it 90 degrees to adjust the tension. If need be, try all four sides and pick the one with the best tension.
If I'm not mistaken, there should be a letter or number on each of the four sides. Once you determine the correct setting for the tension on the belt, you'll need to make sure the other end matches and is set in the same position.
UPDATE
Did some checking online as well, and no luck finding the end caps by themselves. However, it does appear that they are included when you buy a replacement brush roll; as far as I can see that's the only way to get them. I found examples on both Amazon and eBay, although Amazon was by far the cheapest option.
-
[link|https://www.amazon.com/Sionlan-Vacuum-Cleaner-Compatible-Replacement/dp/B0B38G7XGY|Amazon.com: Sionlan Vacuum Cleaner Brush roll Compatible with Shark Rocket HV322 HV301 HV300 HV302 HV305 HV310 HV319 HV320 HV321 HV325 UV450 Vacuum Replacement Parts : Home & Kitchen|new_window=true]
+
[link|https://www.amazon.com/Sionlan-Vacuum-Cleaner-Compatible-Replacement/dp/B0B38G7XGY|Amazon.com: Sionlan Vacuum Cleaner Brush roll Compatible with Shark Rocket HV322 HV301 HV300 HV302 HV305 HV310 HV319 HV320 HV321 HV325 UV450 Vacuum Replacement Parts : Home & Kitchen]
-
[link|https://www.ebay.com/itm/175644706835|Sionlan Vacuum Cleaner Brush roll Compatible with Shark Rocket HV322 HV301 HV300 | eBay|new_window=true]
+
[link|https://www.ebay.com/itm/175644706835|Sionlan Vacuum Cleaner Brush roll Compatible with Shark Rocket HV322 HV301 HV300]
Sorry I couldn't do better, but the Amazon one at $16 USD isn't a horrible price to pay for getting your vacuum back in service.
+
+
UPDATE 2
+
+
Doesn't look like the adjustment procedure I described is applicable to this particular vacuum. The only other possibility I see is that you might be able to adjust the position of the brush motor to change the tension. There are two screws that look like possibilities; if you loosen them you may be able to pull the motor away from the brush roller, thus placing the belt under tension. While holding it that way, tighten the screws and hopefully that will set the belt tension.
@zlarson Ah, I can answer the part about the belt tension. If you look carefully at that end cap, you'll find that the circular part that holds the roller isn't centered on the square part that fits into the head. Depending on which way you put it in, it will exert various amounts of tension on the belt, moving it closer or further away from the drive gear, thus loosening or tightening the belt. Fit it in, then rotate it 90 degrees to adjust the tension. If need be, try all four sides and pick the one with the best tension.
If I'm not mistaken, there should be a letter or number on each of the four sides. Once you determine the correct setting for the tension on the belt, you'll need to make sure the other end matches and is set in the same position.
+
+
UPDATE
+
+
Did some checking online as well, and no luck finding the end caps by themselves. However, it does appear that they are included when you buy a replacement brush roll; as far as I can see that's the only way to get them. I found examples on both Amazon and eBay, although Amazon was by far the cheapest option.
+
+
[link|https://www.amazon.com/Sionlan-Vacuum-Cleaner-Compatible-Replacement/dp/B0B38G7XGY|Amazon.com: Sionlan Vacuum Cleaner Brush roll Compatible with Shark Rocket HV322 HV301 HV300 HV302 HV305 HV310 HV319 HV320 HV321 HV325 UV450 Vacuum Replacement Parts : Home & Kitchen|new_window=true]
+
+
[link|https://www.ebay.com/itm/175644706835|Sionlan Vacuum Cleaner Brush roll Compatible with Shark Rocket HV322 HV301 HV300 | eBay|new_window=true]
+
+
Sorry I couldn't do better, but the Amazon one at $16 USD isn't a horrible price to pay for getting your vacuum back in service.
@zlarson Ah, I can answer the part about the belt tension. If you look carefully at that end cap, you'll find that the circular part that holds the roller isn't centered on the square part that fits into the head. Depending on which way you put it in, it will exert various amounts of tension on the belt, moving it closer or further away from the drive gear, thus loosening or tightening the belt. Fit it in, then rotate it 90 degrees to adjust the tension. If need be, try all four sides and pick the one with the best tension.
If I'm not mistaken, there should be a letter or number on each of the four sides. Once you determine the correct setting for the tension on the belt, you'll need to make sure the other end matches and is set in the same position.