The new pump pulley diameter is 137mm and is a one belt pulley. My original pump has a pulley 145mm in diameter and is a two belt pulley.

My question is: Why does my original setup have two belts used excusively for my power steering pump. Is this a safety feature in case one belt breaks the car would still have power steering? If I used the replacement pump with the smaller diameter pulley how could this effect things.

Thanks