Ok Ill try this here. I have tapped a few early model IFS steering boxes and have had no problems for hydro assist. I tapped my buddy's late model IFS steering box and ran into major problems on the trail. The difference between the two boxes is that there is that a late model has a 10mm allen bolt above the centering valve. I think that is where I f'd up when I put it back together. Does anyone know what it is for and what it does.