No brake or steering power

1996 Astro Cargo brake and steering power failed changed the HYDRO-BOOST , that did not change anything.

Is the pump running? Have adequate fluid?

Is the pump is moving oil? (You can install a clear poly hose on the return line to monitor oil flow.)

does it help to move the steering wheel to a lock/end?

Take the belt off, and see if the power steering pump pulley will pull out (forward). These shafts fracture a lot. It won't leak or make noise, the shaft is just not connected to the vane wheel anymore, and it no pumpy fluid.