I worked at a large ford dealer in Atlanta all through the 80's and 90's when the 555's were new, never ever did we pull the complete rear to do a brake job, follow Ricks direction
and use a good engine hoist and it will go just fine. Do pay attention, several sharp edges on that trumpet housing mating edge, don't re-use the o-rings that seal the trumpet, new brake rod boots, and if it were mine, the axle seals would get replaced while you have it this far down and they're getting disturbed during the brake job. I'd be real pissed if I had to go right back in to do them shortly after all this work. I'm not sure about the dealer your talking to, or is this his way of telling you they don't want to fool with a 30 year old industrial?