Raist,
Was it a caliper that hung or a brake booster that is going south and keeping pressure on the master cylinder? Was it a flex hose or was it the linkage from the brake pedal to the booster sticking? Did the master cylinder bypass or did the fluid boil causing the pedal to go to the floor? It could be both. In my shop because of liability I would start at the brake pedal and work my way out. Everything would come off to be inspected or replaced. It is a 16 year old brake system and my insurance company and I are not going to pay for someone's life time care to save an RV owner money. It will get fixed correctly, which is what I determine to be wrong after a thorough inspection, or not at all. It is not cheap to remove these items for inspection but it is the only way to do the job correctly.
Randy