Rack pinion problems

The car us a 2007 grand prix with 110000miles…It was a gift…anyway hit a chughole at appx 50 mph and broke the right mount bracket…replaced it with a remanufactured cordone brand rack…lasted abt 2months and broke again at the exact same place so i replaced it and replaced the strut on the right side and it broke again at the exact same place…it seems to fit ok i mean im not hving trouble bolting it up…so im thinkin something else is causing this break…but dont know what…subframe? Control arm? Just stumped?Thanks for any input.