I have a Eureka model 4870. Also known as "Smartvac", "Boss", "Pet Lover" . The vacuum doesn't seem to pull as much. It could also be due to a full bag, but if the bag is empty and still weak, check the filter as follows. The front panel (silver/grey on my vacuum cleaner) has a pull tab on one side. You press the tab and the door opens. Nothing is holding the filter, so it should fall out on its own, or it can be poked around the edges a bit with a butter knife. Check filters. If the paper part