99 freightliner problems

So after replacing compressor and governor all that's basically left is dryer? And some valves

 

Is replacing the dryer filter an option? Or just a temporary fix

 

So remove the line from the dryer to the first tank? Or line to the dryer? Because I had air in those tanks spitting milky water out of the small tank oily water from the large tank all on passenger side. Tanks on the driver side had air and no water at all

 

Ok I fired the truck up and removed the small line from the governor at the dryer. Air built up to almost 120 but didn't reach it but held at that psi. No air out of the dryer purge valve but air was coming out of that small line?

 

Would that indicate a different problem?

 

Ok so I left the truck running while I was messing with it. As the air built it started coming out of that little line so I pushed the fitting back on and the purge valve popped. It pushed a little air out but stopped after a few seconds it was building air decently and purging.