[Richard]

yep on the air dryer


Thanks Jon for the info on inlet check valves to the brake tanks.

Russ may be on to something. Brad will you look your original post over and confirm that the info mirrors what is happening? Do you have any more info about the behavior of the system? All of us armchair mechanics are trying to help via remote control and we are no better than the info we have to work from. No offense intended to you, but as you have read the posts and studied the issue more, perhaps something comes to mind.