On my 30, which is a '48 IIRC, the hydraulic control lever is a simple "L" shaped handle on the left side of the dash. There is a mechanism behind the side shield that appears to lock the lever all the way out or in, it has a counter weight with a large hand screw and a hole on the bottom that looks like a rod attached to it. I was thinking it might have been for an implement like a cultivator that would release at the top of the stroke or something. I do know that you'll blow the pump seal if it gets stuck in position, so I've wired the locks open. Any idea what it was intended to do?