wtf **^%$

Your question confused me, so I googled PDR0178 and find that is a brake DRUM, not a HUB. You would normally only replace the HUB if the bearing race spun and ruined it. Look on rockauto. They show many drums from multiple manufacturers. I doubt they are all wrong. Your factory manual should specify the drum size (I forgot). Last time I looked, 9" drums for early A's are widely available and cheap. Lucky you don't need a 10" rear drum.