how do I dismantle a S251i (or related model) Miele vacuum?

I'm not sure which model number I have. Its a blue canister vacuum. Had the same issue I think.

There are 3 screws holding mine together. When you lift the lid to replace the bag, two screws are visible on either side of the lid.
The third screw was between the power and the rewind button. It was down low and difficult to see (use flashlight). After that the top lifts straight up.

Someone else (maybe you) asked about the rewinder - same problem I had. It seems someone tried to push the cord back in rather than push the button up top. The rewinder is held by a single screw to the lid that you just removed. You must also unplug two wires. One of the plugs is marked 'N' for neutral (traditionally the white wire).

The center part of the rewinder comes apart by pressing in two small tabs on the shaft. Careful with the springs - if the spring pops out it could have quite a bit of energy behind it. Slowly feed spring back into the secondary - smaller wheel. Once you have it 99% of the way back, put it back and hook it to the main spool. Pre-load the spring a bit by turning the main spool. I did about 4 turns but it seem I should have done more (need to open the lid again).

If you don't want to go this route, the part number is on the side of the assembly.

Big Smirk
June 2008