Brake air cylinder detached from hub

[Vaflatlander]

To answer your original question how to compress the rod. First be on level ground second shock the wheels securely front and rear thirdly build up air pressure and release your emergency break. That will air the chamber and retract the pushrod if the unit is safe to go under at this time you could replace the bolts

[Bussinit]

Again thanks for the help. And yes I agree that it's quite obvious that I don't know much about my brakes which is why I posted the question that ends with "I'm at a complete loss" but I guess every thread has to have some condescension. So while the helpful posts were coming in, I was doing my research based on the suggestions. That's when I realized that most were describing drum brakes which is when I clarified. Sorry to be so dense. I try and do most repairs myself when I can and this place is great resource. But I know when I'm in over my head and need to hire the work out. However the information is still helpful in that now I am not going to a mechanic saying "something's wrong with my brakes, can ya fix it?" The knowledge also helps you not get completely fleeced at the garage. So to all who offered help, thank you. As always this forum never fails to come through with answers.

[Bussinit]

Ok. So now looking at the diagram in romeofrosty's PDF. I need to get the camshaft (#13) pushed back into the caliper. This camshaft is apparently also called a power screw. It looks like rotating the camshaft would get it back to its proper depth. Basically screwing it back into the piston. Does this sound right? I am going to have a mechanic do it, but I'd like to learn what I can too.