Rebuilding a brake booster is not a easy job lots of parts inside can break easy trust me broke a few over the yrs when doing my time in a brake shop.   The most common thing what goes in the boosters is the diaphragms     Now the one here is out of my xd van sp ot does have to of them and they look worse cause they tore getting them off.   Now first step to getting them apart is to mark the outer case of the booster so u know where the top half and bottom half need to line up,   You will need a press a plate to go in between the press for the booster to be held in using the bolts that hold it to the fire wall, a long flat bar with 3 holes in to go over the studs and the pin that goes into the master (needs to be long for leverage as top and bottom will be stuck together good) now depending on how thick the bar you have is you will a small bit of tube to go over the pin as it will poke through.     Put in the press with a bit of pressure but don't go overboard and then start turning the top half with the bar just watch you don't bend the studs to much if it doesn't move u can use a pair of vice grips to bend the peens on the bottom half a bit to let it move a bit easier     Now once you get it to turn and line the 2 bits up you can release the pressure off the press now don't go to quick as there is a spring in there not as strong as a brake chamber off a truck but will make shoot out if not careful.   Now this is how one will look when one has had brake fluid in it for a bit     Give it all a clean up with the sand blaster, now the main part to be careful with is the bakerlite guts         Sent from my SM-G950F using Tapatalk