I just installed flaps I bought from Tesmania, and I had no problem with the rear bolts/nuts. But my Y is brand new. And I noticed what appears to be some sort of loctite material on the bolt when I removed it. Perhaps, over time, that material becomes stronger and holds the bolts tighter, causing the nut to break loose more easily?Are we hearing about the broken spot welds so much because people only post when it breaks? Are there thousands of people that removed the bolts without incident or are these issues happening to a majority of rear mudflap install attempts?