[Tfrazier]

Well its been a few days and I "think" I made some progress. I found 5 air leaks so far. One that is somewhat embarrassing, since I was so adamant that I had fully tested all of the connections from the air dryer install. And I swear that I did check them, but..... I missed a leak on the fitting at the delivery port. It wasn't noticeable from the front side of the connection, but when crawled around and looked at the backside, there was a whole bunch of big old bubbles. Just took a small turn of the wrench to tighten it up a bit. No more bubbles.
   

The second air leak was at the body of the valve that controls the generator access compartment. Replaced it today.
   

I already knew about the 3rd leak (stair cover valve). I changed out the spool on that one today and, holy cow, the stair cover works great now. This should hopefully eliminate the air leak. 

The 4th one was at a push-to-connect "T" that controls the basement freezer slide. Changed it out with a compression "T".

The 5th leak was at the unloader port of the governor.  Installed a new governor with all new fittings. 

Hopefully all of these fixes will help eliminate or at least minimize my air woes.

Thanks to everyone who chimed in on this thread. What started out as a pretty simple question about my old air dryer turned into a great learning experience for me. I appreciate all of the help.