The belt sits under the brush roll and wears out over time
The belt on a Kirby vacuum is a rubber loop that spins the brush roll — the bristled cylinder that actually picks up dirt from your carpet. When the belt wears out or breaks, the brush roll stops turning even though the motor runs, and your vacuum stops cleaning. Replacing it takes about 15 minutes and costs between $15 and $40 depending on your Kirby model.
You do not need special tools. A flathead screwdriver and the replacement belt are all you need. The belt sits inside the lower housing of the vacuum, underneath the brush roll, so you will need to flip the machine over to reach it.
Key Takeaways
- Turn off and unplug the vacuum before you start, then flip it over so the bottom faces up.
- Remove the brush roll cover by unscrewing the bolts on either side — usually two bolts per side on most Kirby models.
- Slide the old belt off the motor shaft and brush roll, then loop the new belt onto both in the same way.
- The belt should sit snugly around the brush roll without twisting, and the brush roll should spin freely by hand when you turn it.
- Order a replacement belt by your Kirby model number, which is printed on a label inside the machine or on the handle.
Find your Kirby model number before you order a belt
Kirby makes many models, and each one uses a different belt size. Order the wrong one and it will not fit. Your model number is printed on a white or silver label inside the dust bag compartment — open the bag door on the front of the vacuum and look on the inside wall. The label shows "Model" followed by a number like G6 , G7, Sentria, or Avalir.
Write down this number and search for "Kirby [your model] belt" online, or call a Kirby dealer in your area. Genuine Kirby belts cost more than aftermarket ones, but they fit more reliably. Many hardware stores and vacuum shops stock common Kirby belts, so you may not need to order online.
Unplug the vacuum and remove the brush roll cover
Unplug the cord from the wall outlet. This is the most important safety step — the motor can still turn the brush roll if the machine is plugged in, even if it is off.
Flip the vacuum over so the bottom faces up. You will see the brush roll (a wide cylinder with bristles) running across the width of the machine. On either side of the brush roll, you will see bolts or screws holding a metal or plastic cover plate in place. Most Kirby models have two bolts per side, for four total. Use a flathead screwdriver to loosen and remove all of them. Keep the bolts in a small container so you do not lose them.
Slide the cover plate toward the center of the vacuum and lift it away. The brush roll will now be exposed, and you can see the belt wrapped around it.
Remove the old belt and slide on the new one
The belt loops around the brush roll and also around a small motor shaft on one side of the machine. Gently pull the belt off the brush roll first, then slide it off the motor shaft. The old belt may be cracked, frayed, or straightforward loose — any of these means it is time to replace it.
Take the new belt and loop it onto the motor shaft first. The motor shaft is the small metal peg sticking out from the motor housing — it is usually on the left side when you are looking at the bottom of the vacuum. Slide the belt all the way onto the shaft so it sits snugly.
Now loop the belt around the brush roll. The belt should wrap around the full width of the brush roll and sit in the groove or channel that runs along it. Make sure the belt is not twisted — it should lie flat and even all the way around. If it is twisted, remove it and try again.
Spin the brush roll by hand to check the fit
Before you put the cover plate back on, turn the brush roll by hand. Grab the brush roll and rotate it — it should spin freely without the belt slipping or bunching up. If the belt is too loose, it will slip off the roll as it spins. If it is too tight, the roll will be hard to turn and the belt may break quickly.
The belt should be snug enough that it does not move on the roll, but loose enough that you can turn the roll with moderate hand pressure. If the belt keeps slipping, remove it and check that it is seated all the way into the groove on the brush roll. Sometimes the belt sits on top of the groove instead of inside it, which causes slipping.
Reinstall the cover plate and bolts
Slide the cover plate back into place under the brush roll. Line up the bolt holes on the cover with the holes in the vacuum housing. Insert all four bolts (or however many your model has) and tighten them with the screwdriver. Do not over-tighten — snug is enough. If you turn too hard, you can strip the threads or crack the plastic.
Flip the vacuum right-side up and plug it back in. Turn it on and listen for the brush roll to spin. You should hear a smooth whirring sound. If the belt is slipping, you will hear a squeaking or squealing noise — if that happens, unplug the machine, flip it over again, and check that the belt is seated properly in the groove.
Common mistakes that cause belt problems
The most common mistake is installing the belt twisted. A twisted belt wears out much faster than a straight one and may slip off during use. Always check that the belt lies flat and even around the entire brush roll before you close the cover.
Another mistake is ordering the wrong belt size. Belts that are too small will not reach around the brush roll and motor shaft. Belts that are too large will slip constantly. Always confirm your model number before you order.
A third mistake is over-tightening the bolts on the cover plate. This can crack the plastic housing and make it hard to remove the cover next time. Tighten until the cover is snug, then stop.
Frequently Asked Questions
How often should I replace the belt on my Kirby?
A belt usually lasts between one and three years depending on how often you use the vacuum and whether you run it over thick carpet or hard floors. If you vacuum daily, you may need a new belt every year. If you vacuum once a week, it may last two or three years. Replace it as soon as you notice the brush roll is not spinning.
What does it sound like when the belt is worn out?
A worn belt usually squeaks or squeals when the vacuum is running. You may also notice the brush roll is not spinning at all, or it spins slowly even though the motor is running at full speed. If the belt is broken, the brush roll will not spin no matter how hard you run the motor.
Can I use an aftermarket belt instead of a genuine Kirby belt?
Yes, aftermarket belts work on most Kirby models and cost less. However, they sometimes wear out faster or fit less snugly than genuine Kirby belts. If you buy an aftermarket belt, make sure it is rated for your specific model number to avoid fit problems.
Do I need to replace anything else when I replace the belt?
Not usually. However, if the brush roll bristles are worn down flat or the motor shaft is damaged, replacing the belt alone will not fix the problem. Check the brush roll for wear while you have the cover plate off — if the bristles are shorter than a quarter-inch, the roll may need replacing too.
What if the belt keeps slipping after I install it?
First, check that the belt is seated all the way into the groove on the brush roll — it should not sit on top of the groove. Second, make sure you ordered the correct belt size for your model. Third, check that the motor shaft is not bent or damaged. If the shaft is bent, the belt cannot sit evenly and will slip.