When I recently got my state inspection the mechanic alerted me that one of the undercarriage bolts is missing.

Evidently there are four of these? Two (near each other) on each side of the car?

He said they can't tell if it vibrated loose and feel out or if it may have sheared off. He says it would require some cutting and drilling even to find out.

He also said they are not sure what type of bolt it is- exact size or type. 5"? Grade 8?

He gave me the impression it may cost up to two hours labor to fix, depending out what they find. (>$100)

Can someone give me some better info on this? It's difficult for me to get under the car to inspect myself, and I have no experience with them. Bentley doesn't appear to show/discuss these.

My guess is it has been that way for years, this is just the first time someone noticed it. How important is it to replace it? I wonder if it contributes to the vibrations that loosens the muffler system on occasion (loose or lost hangers, etc).

Thanks,
Keith