Been here done that, leave them together, cut some 1/4" thick wood shims to replace the break pads and drop them in the middle, you can use air to get the pistons to creep out 1/4" at a time. You can replace the inner and outer seals but don't pull or loose the o ring between. I would not use any harsh chemicals the air will move them. These things are like rockets if there is nothing in front of them, once one is out if the others aren't close you have a challenge getting the others out.