Having stripped my DC07 down and replaced a poorly motor and worn clutch, plus new HEPA filter, etc, something odd has happened.

After reassambling it all works and picks up but with the premotor filter installed it makes a horn-like resonating noise somewhere between that filter and the upright pipe connecting to the cyclone and collecting box. :(

If you pull off the cyclone and even the post motor filter it still makes the sounds, but remove the premotor filter assembly and it stops. :confused:

Any ideas how to cure this very very annoying sound? :) :)

Thanks.

Silly question, but did you refit all the appropriate seals ?

The support pages on Dyson should be of help as they include good guides.

Dyson Support (http://www.dyson.co.uk/support/)

Thanks for your reply.

I believe so. New postmotor seal as it's glued to the hepa filter and all the other seals were in situ. The suction is now up to par so I would've thought we'd lose it if there was a faulty or missing seal?

I have tried the premotor assembly from my Mum's 07 (later model) and it still makes the horn sound.

The noise seems to come from the vertical pipe connecting the pre motor filter and the cyclone assembly. Like I said, run it without the cyclone and it still makes the noise. Obviously the air is running at the resonant frequency of that cavity. Weird!

Thanks again!

Hi did you sort this. Mines doing the same!