problem with the dually adapters is that it loads the bearings different than they were designed for but if you not hauling real heavy than i don't think it would hurt anything the rear brakes don't do a whole lot if your not loaded heavy, i had done an egr rear disk conversion on my original Dana 70 in my truck i did not notice any difference except for my e-brake was even worse with the egr kit, the only reason I did the rear disk conversion is cause I hate working on drum brakes
Ken