While installing my Artec roof rack, one set of the stock bolt holes in the roof lost the tiny silver "underside sleeve". Both stock bolts now have nothing to grab onto underneath to allow for tightening. The bolts just drop all the way into the whole, there is nothing for them to bite onto. Whatever you call the nut or sleeve on the underside of the bolt whole has dropped down into the area below. There is now no way for a bolt to tighten in the whole.

Is there access to this area from the headliner area? If so, does this even help my situation? Can something be done to the bolt whole from above?

I can't believe those things separated off in the first place - now I have NO idea what to do.

Thanks!

sounds like you need a rivnut.

If you have a telescoping magnet, that will be easiest if you can pull it back to the bolt hole. The headliner would be my the last resort, imo.

For those that read this posthumously:

YouTube

Also this for Pro owners. Which I can't quite understand: https://www.toyota-4runner.org/3200826-post18.html