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If its an earth yes clean it up and re fix it, you'll find heaps of earth straps at different places,
like grill, engine bay dash, front cabin , rear cabin. each section has it own earth, even left...

Yes that the one, don't forget to back cut as you do it.
meaning start cutting thread then reverse your action you will feel it cut
any steel off then screw a bit more and back cut,
keep going...

Was just about to suggest the same. Spray with CRC as well

Re thread the holes with a tap

Now just need to look for postie van with red front recovery points on it LOL