Jeep,I am replacing my power brakes booster and need some advice about removing the power unit from the bell crank.

Hello,
I am replacing my power brakes booster and have a question about the process. My Chilton's manual says you need to "unbolt the power unit bell crank at the dash panel and remove the power unit and bellcrank as an assembly". My question is why cant you just remove the power unit from the bellcrank without having to unbolt and remove the entire unit as an assembly.

Thanks,
JK

My car has 160000 miles.
My car has a manual transmission.