I've been having problems with my wagner wideshot seizing at the piston. The latex paint seeps through, heats and dries stopping the piston from pumping paint. I've tried different lubricants to prevent this, even vasoline, thinking it would form a seal. Now this painter won't even paint a single room without binding. I've always been a bit anal on keeping my tools clean, but thats the way I like it. Point being the painter is not dirty. HELP! Any advice?