What oldskewel said - or just buy new studs and nuts as they are not very expensive. Double-nutting the studs is the easiest way I found to drive them back in without damaging anything. Use two standard (non-locking) M7 nuts. Make sure there is nothing in the hole and don't crank them in too tight, or else you risk cracking the head. The nuts are 11 lb ft, but the studs should not be torqued, just screwed in snug.

I didn't use anti-seize because the nuts are copper and the studs are iron, but it can't hurt.

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2012 xDrive35d
2001 BMW X5 3.0i 5MT
and two 1987 Corvettes - Callaway Twin Turbo and Guldstrand Grand Sport 80
Block Tester