power steering component- what is it?

[motorcritter]

I got my '80 C20 over to my garage area. Looking over the power steering items, I ran across a diaphragm looking item, plumbed into the hose. My Genuine Chevrolet Service Manual (found it behind the seat! With a factory electrical diagram manual! Oh, boy!) shows all sorts of hose, pump and steering box configurations, but nowhere is this item. So, what is it (I think it's probably some sort of buffer or pressure regulator) and is it critical, can I ditch it and not worry? It seems to take up some space that it probably doesn't need to.
Posted via Mobile Device
Posted via Mobile Device