Brake Lines Blown While Towing with Toyota Tundra!!!!

It has been my experience (I am a mechanic) that when a dealer does not have a part and has to order it, that part either has a very low failure rate or so many fail that the dealers can't get one. Being as there is little mention of failures I suspect it is a very low failure item. I found two failures of brake lines with late model Tundras on the net. Both seemingly due to aftermarket exhaust and one of these was carrying a lot of weight in the bed.