My tools of choice for adjusting the reel clutches are a big vise grip or a big adjustable. I think I actually do have a 1 5/16 open end wrench now in one of the toolboxes, but I find myself using the adjustables. The trick is to block the impellers from turning using a broom handle or some other object. I usually don't adjust the reel clutches unless they are *super* loose, as people prefer different settings and I like to let folks make their own decisions. Personally, I prefer mine to be very tight to achieve maximum snow-throwing power --- but I don't have to worry about phone books and other foreign objects in my driveway. I know some of the folks that I sell to use their machines commercially or live in places where chunks of asphalt, phone books, mail, etc. might get in the way. YMMV -- Once I picked up a gallon milk jug with my MA211 and it took an hour to manuever it out of the impeller!