I have a Titan 440i that I use quite frequently, its had a few issues before but I was always able to take it apart and fix the problem- not this time. When I went to clean it after a staining project fluid would come out the outlet line at a decent pace, but it wont fully gain pressure in the hose. I have taken it apart, cleaned everything inside the piston assembly and the filter but it still won't pressurize. Any suggestions?