I've taken my air pump off and want to determine if it's just the clutch/pulley that's failed
I put a 6 mm hex key in the clutch center bolt and tried to unscrew the 19 mm nut holding the pulley on.
The 6 mm hex key turned inside the bolt so I can't now remove the nut holding the pulley on

Can someone suggest what I can do now?

Thanks
Jim

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92 300 TE 4matic