F75 2.8td power steering pump adjustment

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Afternoon all

I guess this is going to sound really dumb but here goes.

I'm trying to adjust the belt tension on the power steering pump but just can't get any decent access to the bolt on the adjuster to slacken it off. Am I missing something simple or is it just a case of persevering and copious amounts of plus gas !

Also what size head should the standard bolt be. The best fit I can get is 14mm but it seems a bit slack, but of course it could be we rounded.

All comments gratefully received

Cheers

Tony