Edited instructions received from Eureka:
"1. Looking at the unit from the front, identify the left wheel well. You will see two ridges in the plastic.
2. Insert the metal spring (it is shaped like a “V”) in the groove between the two ridges, resting on one of its flat sides and with the bottom of the “V” pointing towards the brush roll.
3. Place the holder (white plastic piece) on top of the spring. The triangle-shaped end of the holder should be pointed up and toward the opening of the "V" and the flat end should be slid beneath the ledge at the bottom end of the groove.
However, if you are unsuccessful with installing this in position your unit will still operate but it will not stay in its upright position."
p.s. The parts were pretty well impossible to replace until I completely disassembled the base (after having pressed the retainer button and slid the base off the body of the vacuum) and took the wheel out.
Linda, October 2012