Hello! Long story short, a few month ago I noticed a hum when I pressed my brakes or turned my steering wheel. I'm in a 2001 F250 Ext Cab 7.3L 4x4. I bled the hydroboost and removed the old fluid and refilled with some Merc. Truck drove fine for a long time and hum was quietened down a good bit. A few weeks ago I was driving home and my brake pedal went to the floor. I pulled into a parking lot and noticed steering was tight. Power steering reservior was pretty dry so I added some and limped home. Since I got home I have bled the brakes and now the hydroboost 2 times. The power steering works and the brakes work, but not both at the same time. If I hold the pedal down it does have stiffness, but while holding it down, I can't turn the steering wheel. If I turn the steering wheel and hit the brakes, the pedal goes to the floor. The hum is silent until you turn the wheel to the far right or left. Any suggestions here? Thanks in advance!