Correct old systems wet tank . Newer systems no wet tank and air dryer between compressor and first air tank. Called ADIS and it's just plumb up as per instructions. My 1992 M915A2 has the ADIS system so they have been in using on air brake systems for decades. Also no liquid alcohol in system that is not how the alcohol whiffer system works.
Yes the manufactures are going to new styles of "air-dryers" like the "Bendix AD-IS" system, but according to Bendix it didn't come out until 2007. That means it hit the market. Doesn't mean it was in wide spread use. According to an article in "Fleet Owners" magazine dated 2005 the industry was coming into information about newer style "air-dryers" .
Before I left the Transit department, we had several buses that had "experimental" air-dryer systems installed for evaluation. They where the newer style that had the air compressor line installed straight to the air-dryer. They cost several thousands of dollars.
So, no one has been using the AD-IS system for decades, as it hasn't been out that long. In fact, I would be surprised if more than a quarter of the trucks on the road now even have this type of system on them.
I'd be even more surprised if David's truck has this type of system on it. Unless David himself installed it recently.
I checked on the cost of a new "Bendix AD-IS" unit and they range from $400.00 to $800.00 depending on the model and options.
Considering all the problems these units have I would just stick to the good old tried and true "Bendix AD-9" unit and plumb it in after the wet tank. Mine has worked for years now with no problems as have all the ones I worked on for decades have. At this stage in my life , dependability in my equipment is prized above all else. I just want things to work.
