I have 1999 4WD Blazer that is humming under the driver side when the truck goes right then goes away when going left. I trying to figure out if it is the hub assembly or the bearing? What is the difference? I don't do the work on the truck myself so I am trying to research where it is coming from and as to how much it will cost to fix? Also does both sides need to be replaced if it is only on one side. I know that I am asking a lot but you guys have been helpful on other things that I needed work on.

 

The front hub & bearings are the same thing. When you replace the bearings, you replace the hub. I got mine from advanced auto for about $100.00 a piece. I olny did on e side at a time. Have about 6 months age difference between the 2 sides. Its really not that hard if you have the correct tools.

 

As mentioned before it is the hub, which contains the bearing. If you do it yourself you can order a decent Timken bearing online for about $100 and save the labor. If you pay to do it. The cost will be around $300-$400 with the part being around $150 and labor being the rest. I had one replaced about a year ago at a shop and paid about $350. I just did the other side myself last weekend and spent just $100 buying the part online.

 

Would worn out rotors cause this problem s well? Im just trying to cover all my bases.

 

Rotors should not cause that issue.

 

What about the idle arm?