what booster do you have ?
the booster on my charger was for 4 wheel drums, and you could take it apart by removing a band that clamped the two halves together.
i found a plastic part inside was broken. to fix it, i got the same booster [not sure if it's the midland-ross or bendix booster that comes apart like that] from a '73 dart that had disc brakes, that the guy wanted replaced "just because".
took it apart, the plastic piece was ok, so i installed it in my booster, and all is well on my charger now.
plus, i got a very good diaphragm and other internal parts to put on the shelf in case i may need them in the future.
just tossing this out there in case it may be of help to someone.
expressing my personal experience with this type of booster only. your mileage will vary.