Why your vacuum stopped picking up

A vacuum that has stopped picking up is one of the most common reasons people buy a new vacuum, and one of the least necessary. Motors rarely fail — they either run or they do not — and a machine that still sounds normal but leaves the floor looking the same has almost certainly not broken. Something is blocking it, and there are only about five candidates. Working through them in the right order takes five minutes, and the order matters because each step is easier than the one after it.

Suction is airflow, and that explains everything

A vacuum does not pull dirt with magic; it moves air, and the air carries the dirt. The motor makes a pressure difference, air rushes through the head, along the hose, through the bag or bin, through the filters and out.

That is a single path, and a restriction anywhere along it reduces flow along all of it. A blocked filter at the far end feels exactly like a weak head at the near end, which is why people misdiagnose it — the symptom appears where you are looking, and the cause is usually somewhere you have never opened.

There is no such thing as a vacuum that lost its suction. There is only a vacuum that lost its airflow, and something is standing in the way.

The five-minute check, in order

Do these in sequence and stop when it improves. Unplug it first.

1. Empty the bin or change the bag, even if it does not look full. See below — this is the single most common cause.
2. Take out every filter and look at it against the light. If you cannot see light through it, no air is going through it either.
3. Detach the hose and look down it. Better: drop something small and heavy through it — a coin, a bolt — and see whether it falls out of the other end. If it stops, you have found the blockage.
4. Turn the head over and cut the hair off the brush bar. Almost every household underestimates this one.
5. Check the seals and the joints. A cracked hose, a lid that no longer clicks shut, a missing gasket at the bin — any of these lets the machine draw easy air instead of air from the floor.

That is the whole procedure. In our experience on domestic visits it is a full bag or a blocked filter about two-thirds of the time, hair on the brush bar most of the rest, and a genuine blockage in the hose occasionally — usually a sock, a bottle cap, or a piece of a child's toy.

The filter nobody knows about

Most modern vacuums have at least two filters: one after the bin or bag and before the motor, and one at the exhaust. The exhaust one people find, because it is on the outside. The pre-motor filter is the one that quietly ends machines, because it is behind a panel and the manual is in a drawer.

Find yours. It is usually under the bin or behind a clip on the body, and it will be either a foam disc or a pleated cartridge. Washable ones need to be rinsed and then dried completely — putting a damp filter back is how you turn a clogged vacuum into a smelly clogged vacuum. Non-washable ones need replacing on the schedule the manufacturer states, which almost nobody does.

Here is the tell: if your vacuum smells dusty while it runs, the filters have failed. That smell is fine dust getting past them and being blown back into the room, which is the opposite of the job.

Hair on the brush bar

A rotating brush bar has one job: to agitate carpet so the airflow can lift what is loosened. Wrap it in hair and it stops turning freely, and on many machines it stops turning at all — the belt slips, or the motor protection cuts it.

The fix is unpleasant and takes two minutes: unplug, turn the head over, and cut along the bar with scissors or a seam ripper, then pull the hair out in lengths. Long hair and pet hair wind tightest at the ends, next to the bearings, where they also do the most damage.

Do it every month or two in a household with long hair or animals. It is the single maintenance job with the most visible before-and-after.

Why "it is not full yet" is the wrong test

People change a bag when it looks full. But a bag is a filter as well as a container, and its pores clog long before its volume runs out. A bag at three-quarters is already restricting airflow measurably, and a bag that has picked up fine dust — plaster, ash, flour, builders' dust — can be choked while looking nearly empty.

The same is true of bagless bins: the fine dust that coats the cyclone walls and the mesh is what matters, not the visible fluff. Wipe the mesh, rinse it if the manual allows, and dry it fully.

A practical rule: change or empty at about two-thirds, and always after a job with fine dust. Fine dust is what kills vacuums, and a post-renovation clean will clog a household machine in one afternoon — which is genuinely why cleaning after building work is a different job with different machines.

When it really is finished

Sometimes it is the machine. The honest signs:

• It cuts out when hot and restarts when cool. That is thermal protection, and it means something is still restricted — but if you have cleared everything and it still happens, the motor is working too hard.
• The smell is burning rather than dusty. Stop using it.
• Parts no longer available for a machine old enough that a belt or a filter cannot be bought.
• Cracked hose or body that cannot be sealed. Air will always take the easy route.

Short of those, a well-maintained ordinary vacuum will outperform a neglected expensive one every single time — which is the whole argument of this article, and the reason our own machines get filters changed on a schedule rather than when somebody notices. A vacuum is the one piece of cleaning equipment where maintenance beats money.

Frequently asked questions