Ive just changed the PS pump the strut rod bushings and the disc brake pads why would a 1991 Mercury Cougar still having a growling sound when the wheels are turned from side to side?

Ford power steering pump are moaners, Be it sounds like it has air. To properly purge this system you need to disable the fuel system or disconnect the coil. With the car unable to start try starting the car at the same time turn the steering wheel all the way in each direction. (with engine turning but not starting) this procedure will push the air out of the lines and pump. Dont turn the engine over to long each time Id say 10 seconds and then give it 10 minutes or so so the starter dont over heat. I would do this twice each time going all the way both direction before stopping. What happens is air get trapped and when its runing the pump speed is to fast not letting the air release. When you crank the engine and turn the wheels this allows the air to excape I changed the sway bar links and the sound all but stopped.