I have encountered what I would call an interesting bearing failure on my 2008 Coup. I did some investigating and thought I'd share my story...

A little background on how it all started - I was motoring my way home from a business trip, and since this particular trip allowed me to take an alternate route through some awesome driving territory, I took my personal vehicle so I could at least enjoy myself a little. On the way back, with about 50 miles to go before I pulled into my driveway, I was suddenly presented with one of those situations...a piece of debris in the road, on a downhill bend, in the rain, with a truck right beside me in the only other lane. Approaching the debris at about 65mph, with nowhere to go other than stab the brakes in a corner and tuck in behind the truck, I decided the best outcome would be to just run it over; after all, it just looked like someone's bumper molding, shouldn't be that big of a deal...WRONG! As the object was close enough to see detail, I realized it was a big steel bar, or piece of pipe about 3 inches in diameter. So I just clenched my teeth and pounded over it, the result was a pinch flat on the driver's rear tire and a slight pipe shaped divot in the wheel. Luckily the tire was fairly new and had road hazard protection from the manufacturer for the first 2/32 of tread wear, so no big deal there. Shortly after that, I changed out the tires in the front. Sometime after that I started hearing a strange noise; it sounded like a tag, or piece of tape or something was flopping in the wind under the car on the driver's side. The sound could only really be heard if I was doing over 40mph and next to a barrier or another vehicle and my window was down. After looking under the car for something I picked up, or something that came loose, I could find nothing that would explain the noise. The noise progressively got worse over time, then I started getting another noise, it sounded like tire noise, like I was rolling with some mud and snow tires. Since I changed to new rubber - a tire I've never used before - I wrote it off to the new treads (Continental Extreme Contact DW's). But then the noise started getting louder, it didn't sound like bearing failure, but I started suspecting such. Checking the bearings by grabbing the wheel and trying to measure any lash produced no evidence of bearing failure; every wheel was tight as could be. Finally the noise was loud enough, and it finally gave me the clue I was looking for; it would reduce in intensity when I would turn slightly to the left, but oddly it wouldn't increase when I turned to the right any more than the way it sounded driving straight. So I checked the bearings one more time and decided to rotate the wheels while applying a side load, finally, after almost one full rotation of that front driver's side wheel, I felt a slight crunchiness. Oddly enough though, the bearing still had no play in it. So I swapped out the bearings on that side of the car since I suspected damage from the pipe incident months before, and I figured if the rear hadn't gone yet, it would soon. I put on SKF's since I've read a lot of good things about them.

Now the fun part...being an engineer (mechanical), I couldn't help but wonder how that bearing could be so noisy, yet still be within spec on tightness. I had to get inside and take a look; the following is a bunch of pictures of that process and what I learned along the way...

Not knowing how these bearings were put together, I had to guess my way through the disassembly: Step one - remove the back cover. It's just pressed on with some adhesive, so a little prying with a stout screwdriver did the trick.



Since the bearing was nasty dirty, I decided to clean it up a bit. Here's a shot with the cover off:



Given that the back showed what looked like the steel was worked and peened, I decided to put it on my little bench lathe and hog out the material. But first I had to remove the wheel studs and cut the flange down so it would fit on my lathe.



I took way too much material out, but not knowing how much to remove, I thought better to take out a bunch. Note the shiny area and steps near the top of the bored hole, this is the backside of the induction hardened surface; the tool would no longer cut this material. Time to get the sensor ring off:



That revealed a keeper that retains the bearing race in place, and explained the funny stepped shape of the hardened steel.



Now it was time to separate the assembly, the race is pressed on with a slight interference fit, so I used the bearing retainer bolt holes to jack the assembly apart.



Here's a shot of all the components of the bearing (minus seals):



Here's a shot of the inboard race, cage and ball assembly, notice something amiss?



And here is the culprit of the funny "flapping in the breeze" noise I was hearing...the impact fractured part of the hardened case on one ball, once it lost some of it's "shell" it would just float in the cage and rattle around causing that weird noise. None of the other ***** had any damage!



This last shot shows the outer inboard bearing race (the one that is bolted to the upright), it shows the impact damage, followed by collateral damage from the chunks of hardened steel that came off the damaged ball element only to be run over by the next elements in line. The inner bearing race had similar damage.



So if you have a similar mystery noise, this may be the answer you've been looking for. At the time of my "incident", my car had about 52k on the odometer; it's my daily driver. After changing out the bearings on the driver's side, everything was nice and quiet, even the clicking from the splines on the rear bearing were gone...for a while, it's back again. Oh, and a funny buzzing noise from the duct work under the dash that pops up when doing freeway speeds is still there, haven't figured that one out yet...

 

^^Great post! It's always nice take a peek under the hood and see how things are made.

Thanks for taking the time!

 

Thanks! If you take a rear apart you will find that the retainer is not there to hold it together. That is why you can not run the rears on the front, unless they are the SKF performance bearings from one of the Corvette specialist.

 

Excellent post and photos. Thanks.

 

Great pictures and excellent analysis. I had a front right fail on my 06, but it manifested itself in what felt like a drivetrain vibration above 60 mph. Very hard to track down to the ultimate culprid.

 

Thanks for the education!

 

Great post man. And glad to see those suckers are pretty robust . They should last at least 100K miles without abuse, right?

 

very interesting and the pics make it much easier to understand your detective work. thanks.

 

Thanks for the pics. I had two replaced under warranty at 98K miles. If I would have done the replacement myself, I would have had to disassemble to investigate too. Your excellent write up means I won't need a post-mortem if another one fails.