Do i need a new air dryer?

[Chamberpains]

The compressor pushing oil won't cause condensation to build. But is an indication that it's either starting to be completely worn out and/or something is cracked on the inside allowing oil to get inside the compression chamber. It's a really good sign to pull it apart or replace it. They are lubricated and cooled with the engine oil and sometimes the coolant. So when they completely shi#t the bed they will empty the main engine out in a hurry.

Also the AD9 air dryer was the most common air dryer on trucks for years. When I say they are fully serviceable, I mean you can buy EVERY part on them individually or just the o-ring kits. Whatever you feel is appropriate to rebuild it. It's good to buy another one so you can rebuild the last one and next winter you can just rotate them with a fresh one.

I'm curious what engine you have in that Sterling? It sounds like your bucket truck draws its fresh air from outside the engine intake system. Some engine and truck manufacturers located the fresh air inlet in a really bad spot for getting dry air. ie; under the air compressor or close to the ground instead of directly out of the engine intake. If I remember correctly the Ford Sterling was notorious for routing things poorly. If its one of the poorly mounted fresh air inlets just get proper piping and route it up into a more natural dry spot under the hood. Also make sure if its one that connects to the intake system, that those pipes are solid, tight and not split or cracked. Its not only a leak in the charged air intake system but also a place that moisture and dirt can be sucked in to not only the compressor but the intake of the engine when its not under boost pressure.