I have a 99 ford escort se. I recently had front rotors, brake pads, and ball joints replaced. I filled tires to psi that was listed on the tires. I hear a whirring noise comming from front left. I've been told it's most likely a bearing. My question is : Is it better to have just the bearings put in? Or can I just buy the whole part and get it replaced? Which makes more sense? I'm a little unknowledgeable about cars when it comes to this.