not sure if it is the hub & bearing, while driving i hear a humming sound from the left rear??? if this is the problem, would i be able to fix it on my own or would i have to take my car to the shop. And tools would i need?? i was planning on buy a air compressor for around $200 or so and some air tools, would this be enough or would i need some other tools?? any help or suggestion would be appreciated, thanks...