Vacuum not picking up

At the top of your wand, do you have a plastic swivel that cover a hole in the wand? This is for when you are cleaning curtains, and if that is open, or cracked you will loose suction there... also check your hose for cracks, or breaks. If it were in the shop I would put a gauge on it... normal suction is about 80-95 inches of water lift at the end of the hose. Once you have check each section of the hose, and wand, check the housing for cracks, a missing gasket (Very Good Reason For Lack Of Suction) As to your Filter, how long have you used that one filter, you can clean them for a while, but once a paper filter gets full of FINE dust you won't get it all out, you will have to replace the filter itself at that point. I hope this was helpful.