AC Idler pulley
 

I have a 1976 W115 240D. The Idler arm pulley is starting to make a noise in the mornings at start up. I have ordered a replacement INA pulley from 2 different vendors. I keep getting a 9.5 mm diameter pulley but the pulley on my car is a 8 mm diameter pulley. The part number I receive is 535 091 200. Has anyone ever had this problem? I don't know how to proceed to get the correct size.

Thanks for the help.

Can the bearing be pressed out on that vehicle> If so, you can source a higher quality bearing and press it in.

Possibly you can specify to your vendors that you specifically need an 8mm diameter pulley.