Mercury - Trim and Tilt Cylinder End Cap Hydraulic System Component Aluminum Alloy 8M0021648. Overview. Any boater who spends enough time on the water knows how much you rely on your trim and tilt system. It is one of those things you barely think about when it is working right, but you feel it immediately when something is off. A smooth trim lets you settle the bow exactly where you want it-lifting over chop, easing into shallow water, or finding that perfect running angle on a long stretch of