Originally Posted by AP - Chris_B

Vehicles that have a drum-in-hat (DIH) mechanism for a parking brake, like most Nissans do, rely on the hat portion to stand up to the load put on them by the brake shoes. There a hill-holding requirement in some U.S. states that test for this as part of an annual inspection. And, some people actually use the parking brake to help rotate the car in slow corners. I know it is hard to believe and I'm sure you have never personally done this (), but it has been known to happen.

Although lighter, aluminum would not survive nearly as well over time in this environment. The first issue is abrasion from the shoes once any plating wore through. The second is the possibility of the parking brake being set after hot lapping (I suggest never doing this regardless of hat material). If done, there is a good chance that a very hot aluminum hat would distort and go out of round. Iron hats don't suffer the same fate as they pretty much last forever. There are some cars for which aluminum rear hats make sense, but the Nissans did not meet all of our qualifications for such.

Chris