I have 6 brand new 2012 Hustler Super Z's with the 72" rear discharage decks. Last week I had 3 bolts that hold the blades on break, and 1 the week before for a total of 4. Im curious if anyone else who is running a Hustler is having this problem. They are Grade 5 bolts. I have been using Hustler super z's for the past 7 years and have only broken 1 or 2 during that time, and with the new mowers I have already broken 4 this spring. They do have the Kawasaki FX1000 engines, So maybe it is contributed to the added horsepower driving the blades, or a bad batch of bolts. Just curious if anyone else has had this problem.