Visit the parts section of sears.com and from that website, you might be able to find a diagram of the exact model you have.
On the Kenmore 116 2561190 canister vacuum I have, there are two screws underneath the hinges of the large cover that you lift to change the bag. Lift the cover all the way and see if you can flex the hinges some so you can remove the cover enitrely. It makes it easier to get to those screws with the cover removed.
There are also two screws underneath the on/off pedal at the rear of the canister. To remove the pedal get a flashlight and look at the front of the on/off pedal and you should see some retaining tabs. Get a couple of screwdrivers and inbetween the pedal and the top rear cover housing pry the tabs of the housing forward so that they will release the tabs of the on/off pedal. When I did it, I started on the left side and made my way to the other side. I used one screwdriver to keep pressure on the pedal towards the rear of the vacuum, and used the other screwdriver to push the retaining tabs of the housing forward to clear the tabs on the pedal.
Once you get the on/off pedal off, you'll see the two remaining screws that need to be removed to get access to the motor or power cord assembly.
Randall
August 2008