Wind Tunnel U5723-900 part missing?

\015 I was given this vacuum and it works great except for the hose doesn’t have any sucking power. The dirt cup doesn’t seem to fit into its space quite right. I put the dirt cup in and move the lever over and a shield comes down to hold the cup in place. Except that it doesn’t fit tight, it’s like there is something missing, a seal or something?\015 – Kenmore Progressive Bagless Upright with Inteli-Clean SystemVacuum