Why does my vacuum have no suction even with a new bag?

Most likely a clogged hose or a saturated pre-motor filter. Check those next. If both are clean, look for a hose crack or worn seal.

How do I clean a vacuum filter?

Foam pre-motor filters typically wash with cool water. HEPA post-motor filters on most Mieles are not washable; replace per the manual.

Is loss of suction a motor problem?

Usually not. Motor failures are the last suspect, not the first. Work through the bag, hose, filter, belt, and seal first.

Diagnose

Why Your Vacuum Lost Suction (and How to Fix It)

When a vacuum loses suction the cause is one of six things in this order: a full bag or full canister, a clogged hose, a clogged pre-motor filter, a worn brush belt, a cracked hose or seal, or a failing motor. The first four you can check yourself in under five minutes.

Causes, ordered by likelihood

Full bag or canister. The cheapest and most common cause. Replace the bag, empty the canister, and test.
Clogged hose. Disconnect the hose and look through it. A flashlight from one end shows blockages.
Saturated pre-motor filter. Pull the filter and inspect. A solid dust film means it's saturated and needs cleaning or replacement.
Worn brush belt. On uprights, a slipping belt drops the brush bar speed and reduces apparent suction.
Cracked hose or seal. Run your hand along the hose. Air leaks feel cool. Common at the wand junction.
Failing motor. If the first five are ruled out and the motor sounds weak or strained, the motor is the next stop.

What to check at home

Empty the bag or canister and try again.
Disconnect the hose, look through it, clear any visible blockage with a broomstick from one end.
Pull the pre-motor filter. If it's gray and dense, wash it (per manual) or replace.
On uprights, check the belt: a slipping or broken belt is a fast fix.
If all four pass, the issue is likely a seal, hose crack, or motor. Bring it to the shop.

When to bring it in

If your DIY checks pass and suction is still weak, the issue is upstream of normal user maintenance. Bring it in. Diagnosis is free and most cracked-seal or worn-motor jobs run $50 to $180.

Call (703) 931-6100 Walk in to the shop

Brand-specific notes

Miele: The Complete C3 and Guard L1 lose suction most often from a saturated AirClean filter. Replace the HEPA AirClean filter at the same interval as the 4-pack of bags.
Dyson: V-series loses suction from a clogged post-motor HEPA filter (washable) or a cracked cyclone seal. Wash the filter monthly.
Shark: Navigator and Rotator lose suction most often from a clogged hose channel between the canister and the wand.
Central vacuum: Central units lose suction from clogged inlets or a leaking inlet door gasket. The single-inlet loss is a different diagnosis from whole-system loss.

Common questions

Why does my vacuum have no suction even with a new bag?: Most likely a clogged hose or a saturated pre-motor filter. Check those next. If both are clean, look for a hose crack or worn seal.
How do I clean a vacuum filter?: Foam pre-motor filters typically wash with cool water. HEPA post-motor filters on most Mieles are not washable; replace per the manual.
Is loss of suction a motor problem?: Usually not. Motor failures are the last suspect, not the first. Work through the bag, hose, filter, belt, and seal first.