Subframe bolt fell out?

[Theodore.Haug at rrd.com]

Here's hoping someone has run into this before....  1990 Audi 100 (non
quattro) was in for it's inspection on Friday.  The car in up on the lift
and we go to remove the the left front wheel, and notice a lot of movement
in the subframe.  Low and behold, the left rear subframe bolt has fallen
out.  Oddly enough the car drove fine, so I don't know how long the bolt
may have been missing.  But, it must have been working itself loose for
awhile, because the replacement bolt no longer draws tight in the threads.
Has anyone run into this before, and have any suggestions.  Drilling it out
and retapping may not work because the bolt still has to go up through the
subframe bushing.

Any thoughts would be really appreciated.

Thanks in advance.

Ted Haug
90 100
87 Coupe GT
90 V8 quattro
94 Cabriolet
(headaches aplenty)