[77newell]

You conclusions about the relationship of the service tank and the brake tanks is consistent with my own understanding which is why I have been focused on the brake system which in theory has each system sealed from the other and at least from what I find from vendor literature they indeed are separated by either separate tubing or o'ring seals in the common devices such as the brake treadle and the e-brake/parking brake valve. The brake system should, and does leak down very slowly and I'm wondering if that is just the way they are given all the parts and pieces involved. Still, my engineering mind wants it perfect. I suspect this leakage has probably existed since I've owned the coach and only became apparent now because of my diligence in eliminating the non-brake systems leaks. If so, I should interpret this as a sign of great success instead of kvetching about it.