One of the rear brake cylinders was leaking a little bit on my 1973 Mazda 808 so I needed to replace it.
Those bolts come out then put them in the other hole and thread in to pop off the drum. Works great.
Top spring comes off first, then bottom then the side ones.
brake shoes off
undo the brake line then the two bolts holding the cylinder
brake cylinder off
new versus old brake cylinder
New brake cylinder in and all the springs back on. That top one is a pain to do. Bottom first, side ones next and then top.
All done. Now to bleed the brakes.