The bomb itself has two compartments inside, one filled with nitrogen and another is where the fluid goes in. As we all know the liquids (especially the ATF) cannot be compressed the way gases can, the bomb operates on this principle. The pressure is built up by compressing the gas and when you need emergency braking power or when the engine is shut off the pressure is released thus providing you with power assist. But what goes bad exactly is the diaphragm which devides the compartments. You are not thinking of fixing it, are you?