hello everyone, i recently picked up a free ride mower. I'm slowly trying to bring it back to life.  iI took a look at the brake assembly to see what condition they were in and to me it looks like its missing pieces.  I've seen youtube videos and those brakes have a circular i guess you would call a caliper as well as a brake pad.  Mine does not have those things, it just has two pins and a metal bracket that goes over them. My question is, is that how its suppose to be or are there components missing?  I've enclosed a couple of pictures. the second picture is with the bracket removed and shows just 2 pins. i thought there would be something circular there to compress the pins in. i'm new to this and would appreciate any feedback.

There's nothing circular in there.  
 
You are correct about the disc.  There should be one pad (very small) and the two pins
usually rust up in there so that has to be removed and cleaned.  Re-grease pins to slow corrosion.
 
Now, that main arm, (about 1" wide) is not flat and is "tappered in" on opposite sides down at the 
mounting hole.  When the brake is applied, the arm moves, the tappered in part pushes in on the pins.
The pins then push in on the pad, then the disc.  
 
 The nut holding the plate on is also the adjuster.  Tighten in the nut, the brakes are tighter.
You want a happy medium where you can apply the brake and the manual "lock" will apply and stay.
If too tight, the brake will work but will not allow you to lock it on..
 
Pull the arm and aluminum assembly off. Clean the corrosion off real good, wire wheel or sand off
all corrosion off the arm..
 
.

 Thank you for the response scott, i removed the crown nut and plate and this is what's behind. in videos i've seen the whole caliper come off and it has the pins(usually seized) in them and on the back side there is a metal plate and the brake pad.  This here looks like the pins are attached to a whole unit which doesn't separate.

Part #59 is apparently your brake rotor.  This, looking at the parts diagram, seems to be under that yoke sticking out (picture sucks):
https://www.ereplacementparts.com/craftsman-917271141-lawn-tractor-parts-c-158286_174089_461578.html 
 
I've never seen this design before, so maybe a shop manual would help, or just go slow
and take that yoke off to access everything..
 
.
 

will do, appreciate your help.