Socket size for Tension and Idle pulley removal

[NYCSterling]

Hi Folks,

I need to change my tension pulley and idle pulley asap and I would like to have all the needed tools beforehand.

Does anyone know what socket size is needed to remove the tension pulley and the idle pulley?

Just called BMW and the parts are in stock...
there are 2 sets of belts...
The Alternator belt has the Tension($157) and Idle Pulley($67)

and AC belt has another Belt tension pulley ($157)

I have the screeching sound for 2 days now and need to do the test to see which one needs changing.
From what i read, i need to slip off the belt and try to spin them..and they should NOT be able to spin freely.