Recently my car was making a grinding nose that I narrowed down as coming from the rear left wheel. I drove around with it for a while until finally my car started bobbing from side to side. I took it to a mechanic as soon as I could and he showed me what was left of my wheel bearings-some shavings!! He is ordering new bearings to put in and he said that I also might need the outer part of the drive shaft. Do i really need the drive shaft too or is he just trying to scam me for a few bucks? Also should I get them to check all of the other wheel bearings if that one was so bad?