I've had my roof rack off a few times and was lucky to not have many problems with the free-spinning rivnuts that are widely reported. That being said, I did have ONE that broke free the first time, which I was able to reach with a pair of vice grips without dropping the full head liner. Ironically, I also had one that attaches the wetbox to the roof rack spin on me.
I removed the rack to tighten up my home-brew insert a few months back and I am 99% sure I crossthreaded at least a few of the bolts on their way back in. The blue locktite was bound to do that eventually, since I have removed the bolts so many times.
So, with my new roof rack on the way, I am contemplating replacing as many of the rivnuts as I can before installing the new rack. I understand there are at least a couple that can't be reached easily from inside.
I was wondering if anyone has done this and can give me any pointers. I read the "how to" on TNX which isn't very pic heavy and left me with some questions still. I plan on doing this in the next week or two, as soon as I get some new rivnuts ordered. My understanding is that I just pull the old ones out (trying not to enlarge the holes in the process), put the new one in the hole and use a wrench to hold it down while I drive a bolt into it to mushroom it out inside the cabin? Anything more to it than that?