Mercury - Power Trim and Steering Fluid Universal Marine Hydraulic Formula 858074K01. Overview. When you are running your boat through narrow channels or backing into a tight slip, precision matters. You can feel it in every turn of the wheel, every lift of the engine. That smooth, responsive motion comes from more than just good mechanics - it comes from the right fluid working quietly behind the scenes. Mercury Power Trim and Steering Fluid is that dependable partner in every trip. It's the fl