It can be one of two ways, threads in the flange or a nut spot welded to the flange. What I recommend is using a penetrating fluid on them a day before working on it. See if they will come out. If they don't and break, just drill the bolt out and replace it with a new nut and bolt.
Let me know if you have other questions.
Joe
Thursday, March 25th, 2010 AT 10:17 PM