According to post 6 a master and booster were needed and the problem was resolved.
Were the master and booster actually replaced--says only that they were diagnosed as "bad".I installed a new wheel cylinder pretty quickly, but still couldn't get the rear brakes to bleed. I got tired of messing with it so I limped the truck over to my local mechanic who said the master cylinder was bad, and the the booster had a vacuum leak. What I thought was going to be a quick fluid refresh turned into something quite a bit bigger (and pricier). Good times!
I don't see that the original problem has been resolved. It may be that the description of what happened is lacking detail.