I have a 48" DD walk behind 15 horse. I was mowing this afternoon when there was a horrendous noise like I had picked up a piece of wire or metal in the mower deck. I disengaged the pto, stopped the forward progress with the foot pedal and attempted to release the hydros so that I could move the unit by hand. I discovered that the eyebolt that links the right hydro release valve had sheared off at the mounting point on the hydro. What caused this failure? I use this machine very lightly, about 50-60 hours a summer and have only had a belt failure in the past. I maintain the unit according to the owners manual and take great pride in owning one of the finest pieces of equipment I have ever mowed with, Can you help me troubleshoot this problem? My local dealer is C & B mower in Lima NY. Any advice would be appreciated.