lost a caliper bolt....

I lost a caliper bolt on my 97 XJ 4.0L auto 4x4. it is the lower bolt on the passenger side. I went to reinstall the caliper the other day and the bolt appeared to just keep spinning and spinning when I put it back in. I checked to make sure it was lined up withe the hole in the knuckle and it was so I was thinking that the hole might have been stripped out a little bit. Well I crawled under the Jeep two days ago and saw that the bolt had gone missing.

My question is what do I do now? I have seen those thread repair kits at autozone that look like they might work but I don't know what size to buy. I went ahead and bout a new set of caliper bolts so I got that far just need to actually get the knuckle fixed to accept the bolt again.

I think the thread size is M8x1.25 but I won't know for certain until I get home and check my thread repair kit. I have had to do this to 2 of my caliper bolts. Installation of the thread repair kit is easy.