OK, just posting my experience with what I thought would be a simple task to adjust parking brake on my 2012 E350 RB. This post seems to have the most info so thought I share it here.
Like others I wrongly assumed it would be an easy task to simply adjust some turnbuckle along the parking brake cable. Next thing I know I'm searching here for solutions and discover the Ford drum brake within a disc brake rotor solution.
My adjustments were made with both rear wheels raised and removed.
Not sure if its because of my later year or semi-float rear axle, but first thing I noticed is my axle has the low easy access adjustment port on the driver's side, not the passenger side. So that side was pretty easy, turning star nut up (clockwise when looking from front of van).
Passenger side was quite a bit more complicated. I initially found the adjustment access port so inaccessible (up high in the wheel well) that I immediately moved on to the alternative method of removing the brake disc rotor and doing the adjustment with full access to the components. Except I discovered that wasn't a piece of cake either and couldn't remove the rotor with reasonable force and decided to take another look at the existing adjustment access port.
Having more motivation and finding a way to affix a mirror I found a could hold a flashlight in one hand and a small screwdriver in other and get to the star adjuster. Note that it took quite a bit of mental training to get used to making adjustments while looking in a mirror but I eventually got used to it.
The hard part was trying to figure out if adjustments should be clockwise like drivers side or opposite. In the end It turned out clockwise was correct, but that was turning star adjuster down because it was the opposite side. It was also hard to tell if I was actually turning the adjuster or just slipping and scratching the surface.
In the end I moved adjusters far enough to engage brake and then backed off about 6-8 stars. In cab, parking brake went from being depressed to floor to about 50%. Will confirm performance tomorrow in my sloped driveway where parking brake was beginning to feel iffy.
Here are some pics of my setup for accessing the passenger side which had the harder access on my van. As I said, not easy, but definitely doable.