I am replacing the core in my radiator... however ive come to a stop trying to remove the cage from around the core. This X-brace seems to be held in place by some unknown fasteners... Need to remove this x-brace somehow. Are these rivets crimped on and need cutting off? Looks like a stud is going through but inserted in the back side then this cap on top. Anyone ever encounter this? Is there a trick before I slice it apart? Thanks.