Q: I need to replace my serpentine belt, it with the power steering pump deleted. What size belt would I need? 2007 Mercury Milan

Hi there - this may or may not be possible. Bypassing the power steering pump may route the serpentine belt in conflict with other rotating components on the engine. Using a "soft measuring tape" (like a tailor uses), measure the distance around all but the PS pump, following the same path the original serpentine belt follows, minus the PS pump. Do this with the belt tensioner in the "full tension" position. Take this measurement (in millimeters) to your auto parts store, and ask for a belt with this length, and the same number of grooves as the stock belt. This may require trying several belts (assuming no conflicts) to get one the length you require. Will likely be simpler, and not that much more expensive, to replace the PS pump. Good luck!