413 bolt question

["Jennifer Allyn" <gearhead.girl@xxxx>]

1962 413 top alternator bracket slider adjustment bolt.
The one that goes into the water pump housing seemed to have decided to
break off while Jennifer was driving this afternoon.

Who can tell me what the bolt size is and do I use a flat AND lock
washer?
Who has suggestions on how to drill it out, with out pulling the
radiator?

Thanks!
Matt Allyn


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