GMC Truck question...maybe for a GM tech?

My 1998 GMC Sierra Z71 has a two fold problem that I need to see if someone can help me with...... My power steering is real hard to turn unless the engine rpm is around 1000 and it makes a growling noise kinda like when one is low on fluid even though it is full....Second the brakes have a new master cylinder but the pedal is not consistent and the anti lock brake system kicks in even when there is no danger of sliding the tires....it sounds like a ratcheting noise of some sort....when I take the fuse out of the anti-lock brakes in the main fuse box the noise goes away but the Pedal pressure is inconsistent and you have to pump the pedal to make sure you are going to have brakes...Any ideas on this would be greatly appreciated....Has new master cylinder and new brake pads and shoes....Thanks in advance