Compressor only goes to 220 bar and won't go any higher. Plugged fill whip and tightened down air bleed on filter assembly and it went to 4500 PSI...but I saw it bleeding down slowly. Sprayed commercial leak detection fluid all over unit and could see no leaks. HOWEVER, I could feel air escaping from the bottom of the filter cartridge and from an opening I assume is what opens when you unscrew the air bleed valve. The air bleed screw is just tightened firmly but I have not reefed on it. Do I just need to get more agressive with closing the air bleed screw or is there na O ring or something inside there that has to be accessed and replaced.