To remove the studs, fit two nuts onto one stud and tighten them up against each other, but don't over do it. Use plenty of penetrating oil, then gently work the nuts back and forth until the stud starts to move, then start, again gently, removing the stud. To refit them or fir new ones, degrease the threads thouroughly, both male and female threads, and fit studs the same way you removed them, but use thread lock too, to prevent them from coming out again.
