[Shamu406]

Adrian,
I never suggested that you go under the coach until it is cribbed up safely.  I'm glad you felt uncomfortable as that would be a very dangerous and possibly deadly practice.  

As I said not all coaches have the air tank in R-1.  It is about 50-50.  Evidently you don't.  You will have every other air tank I described.  The two black oval air tanks you saw are the air tanks for the front brake system.  The two crossmember tanks you will not see until you are able to get under the coach.

Look again on the rear wall of the left wheel well.  The air dryer with the desiccant filter on top is on the rear wall inside the tag tire.  If you still can't see it, raise the coach and use a flashlight.  To change the filter I raise the coach all the way with the leveling system, crib up the coach as described and I can change it from the side of the coach without getting under.  The filter IS NOT under pressure so you do not need to drain the air system to change the filter.

Hey Steve,
John here. Not sure who Adrian is, but I think your post was meant for me. I'm going to crib it up as you suggested.
I checked the right rear tank in front of the drive wheel, and it did have about a shot glass of rusty water. I did find the air dryer and filter behind the left tag wheel, the whole unit looks like new.  I called the previous owner and he told me he had it replaced just before I bought it, he replaced the whole unit with a WABCO dryer and filter, but its probably due for a new filter, since it has been in for about 2 years or so.