I want to replace my rear shackles when I replace the leaf springs in the coming weeks and I am unsure how to do them. Alot of people told me that if I snap the upper bolts I am going to have to cut a hole in the opposite side of the frame. Can anyone point me in the direction of a good write up or video on how to remove and replace the rear shackles? Thank you.

 

Just undo the bolt, if it breaks you'll have to get the remnants out of the nut.. simple as that.
I had way more trouble with my front bolts.
Go buy a can of pb blaster and start liberally spraying anything you may touch