Yeah, this is an old thread, but I ran into this problem after ECXC and made a little video:
Idler Arm Banging Now if you're bored:
X-Treme Idler Arm Banging I tighted as much as I could, though I'll try using a breaker bar and later an impact wrench. I just feared breaking something. Also, anyone know the exact size for this bolt is? Is it metric/standard?