Squealing Rear End on 2009 Hyundai Santa Fe AWD

I commute 35mi everyday from NJ to King of Prussia, PA a majority of my time is spent driving up the schuylkill expressway. It’s some stop and go, but at times it’s a winding raceway up the valley. Yesterday about 45mins/25 miles into the drive I notice a squeak that’s in rhythm with the speed of my car. Braking would dampen the noise, but it would return. I drove it over to the dealership where I work. They say they’re booked, but they might have time to look at it in the afternoon between some other appointments. They call me about 2:30pm and say they drove the car around at 30mph, 40mph, and 50mph. No squeak. They say they’ll take off the tires to look around. They call me again in 30minutes to say the car is ready, $50 later they didn’t find anything. My drive home was quiet. Btw it was damp, but not raining yesterday morning. The afternoon was in the 80s and sunny.

This morning it was very damp and misting on the way to work. As I slowed for a toll booth the squeal reappeared and lasted for a few minutes as I got back up to speed. Then it disappeared. I had an idea it was a bad wheel bearing. I remembered reading that driving the car in circles clockwise and counter clockwise could help identify a bad wheel bearing. I found an empty lot near the dealership and proceeded to drive in circles 25mph, but fairly tight. Not a peep out of the wheels except for the occasional squeal of the tires. Disappointed with my test, I drove right past the dealer quiet as a mouse.

Finally as I pulled into my work parking lot the squeal reappeared. I found an empty section of the lot and retested my circle hypothesis. Going in circles actually quieted the squeal in both directions. As the car returned to a straight course the squeal reappeared.

Sincerely,

Feels like he’s going in circles

Have your brake pads–both front and rear checked.

What you describe is consistent with badly-worn brake pads, so you should eliminate that safety hazard before you do anything else. It could also be related to dry wheel bearings, but I would recommend that you pay attention to the brakes first.

The audible wear sensors in the pads make an annoying sound in order to alert you to the fact that they will soon be worn down to nothing. The noise is variously described as a cricket-like sound and as a squeak. And, when the brake is applied, the noise disappears–temporarily–only to reappear when the brake is not applied. When the brake pads are totally worn down, the noise disappears, as the wear sensors are also worn out. At that point, you will ruin the brake rotors from metal-on-metal contact.

I recently purchased an 09 sante fe awd and heard the same noise from the rear. I had the dealership change the rear pads and rotors still the same noise. The rotors are from hyundai and the pads are just standard replacement pads. The front pads were checked and found to be fine. Seems like this noise is a common problem. Has any one put drilled slotted rotors or aftermarket calipers on one of these to fix the problem?