HELP!! have video - cant figure out rear brakes e450 dully

It's normal. They have pins, which is oddball..

Here's a good how-to:
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/26817967.cfm

Note, those calipers can be trouble - if they're dragging/binding, might be worth getting some high quality replacements. Pistons were steel or composite, depending on the year and gave me fits in the front.

Not oddball at all, Ford used this method of caliper mounting for years. My '91 Ranger has the same thing. They are extremely easy to remove as they are simply two pieces of metal <> filled with elastomer in between. The ends are tapered slightly, and each end of each piece of metal has small tabs bent outward to keep the pins from sliding out.

Take a large punch or drift and drive them inboard till they stop, do not force them. Then hit the outer apex of the > at about a 45° angle, it will compress the elastomer enough to allow the tab to sneak into the caliper or bracket then go to the other apex of the same pin

As already noted, the pistons in the calipers can sieze, especially when hot, as they are made of phenolic material. I've had it happen twice on the Ranger when I was in downtown Atlanta interstate traffic. They sieze up and you gotta let them cool to get them to release. Each time the calipers had about 100k miles on them. Just replace the calipers and be done with it.

Charles