Bolts alternator adjuster

I understand that there is a bolt snapping issue then you upgrade your alternator belt adjuster. Something like this:



http://ift.tt/1DSJmmE



I didn't get bolts with mine and I want to use hardened bolts (12.9).

Is there anyone who can tell me what thread they are and what length.

Saves me the hassle of taking them out and then getting them.

I want to get them before I start spanner-ing.

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