hello, have a 88 delta,put new power steering pump in , works as far as the effort to turn easy is fine , makes a humming nouse , and when you turn of motor, it blows back through the to p of the pump,is also very foamy, any body know whats going on/ thanks will.

 

Firstly, I do not know how the PS pump and res are setup in your car, so my ideas are general thoughts. I do not know if you have a seperate pump and res or it they are combined.

My first thought is that you may have an air leak on the draw/suck line from the res to the pump. Foamy PS fliud is normally because the pump low on fluid or pulling air in. It may not show and fluid leaking on the line since there is not any outward pressure. When you shut off the engine the fluid is not being drawn in and the air that is keeps expanding due to heat and pressure changes and blow out the top of the res. If you have NON foamy fluid to the cold level in the res before you start the engine I think you will find an air leak on the draw side of the pump.

Adam