The most common cause of repeat bearing noise is not torquing the axle nut correctly. The value is very high, typically around 180 foot pounds, and on some cars as high as 240 foot pounds. Even when the proper click-type torque wrench is used, a lot of people set the tire on the ground to hold the wheel from turning while they tighten the nut, but by that time the damage has been done. There must never be any vehicle weight on that bearing unless it is tightened to specs.
The easy way to keep the axle from turning when tightening the nut is to stick a screwdriver or punch in one of the cooling slots of the rotor.
The next problem is it is somewhat common for the sound to transmit to the other side of the car so you replace the wrong bearing. With bolt-on bearings, you can just put the old one on the other side, but pressed-in bearings are destroyed to remove them.
There is a tool you might be able to borrow or rent from an auto parts store that borrows them called the "Chassis Ear". It is a set of six microphones, a switch box, and headphones. You clip the microphones to suspect points, then drive around while listening with the headphones. You can move the microphones around to zero in on the source of the noise. Be aware that many mechanics have never seen or even heard of this tool. Suspension and alignment mechanics use it to find rattles, squeaks, and other noises.
You can also often feel the noisy bearing by spinning the tire by hand while you feel on the coil spring. I prefer to run the car on a hoist, then listen next to each bearing with a stethoscope. One will sound rather odd, but then the other noisy one will be real obvious.
Friday, July 10th, 2015 AT 10:08 PM