Fan Belt Adjustment Nut
I was replacing the drive belts on my 1993 4.5l petrol LC and
was attempting to loosen the lock bolt on the adjusting mechanism
which moves the alternator to give the correct tension on the
belts. I was using a standard 12mm socket and to my surprise
(horror) I burred the end of the bolt.
I contacted a friend who works for a Toyota service place and
he told me it was a common problem. The head of the bolt is narrow
and apparently tapers for some reason ( perhaps to clear the
belts??) . You need to use a double hex socket to lessen the
chance of burring or a star drive head ( the bolt head has a star
drive hole which is difficult to see at first glance).
I managed to remove the bolt using a star drive and I replaced
it with a standard bolt. It still seems to clear the belts OK.