Okay, found a picture that might give you an idea on the "head" part of brown Kenmore. You can see the 2 screws that I had to remove to take the entire part off.
Labeled as follows:
1. There is a "peg" from the tension dial that rolls along a flat spring (2) attached to the tensioner. This puts more or less pressure on the spring, in turn putting more or less tension on the disks in the tensioner. Yours probably works a little differently because it's a lever. I haven't pulled apart one like that before.
2. This is the flat spring attached to the tensioner. It kind of fits through a hole up into the machine.
3. Here you can see the back of the tensioner from the inside of the machine "head."