Bit of Background: 2000 4x4 Blazer, 140k miles. Last week I changed the hub bearings because the drivers side was very loud and had terrible vibration. At the same time I changed the brake pads. The CV boots on the drivers and passenger sides looked fine, definitely no tears. Drove the Blazer for about 15 miles or so over the next few days and it felt like a brand new car again. Whisper quiet.

Just two days later, I embarked on a 250 mile round trip. About 80 miles into the trip I notice that there is a bit of a whirring noise and maybe slight vibration in the floorboards of the drivers side. I thought maybe it's my imagination and I'm just trying to find something wrong. I pull into a rest area for a few minutes and when I go to leave, I turn the wheel hard right while backing out a parking spot and it felt like the e-brake was on. I mean I have to give it some GAS to get it to backup with the wheel turned. Anyways, once I straightened out It loosened up and I was back on the highway. Now I'm definitely feeling the subtle vibration in the floorboards and there is a definite high-pitch whirring noise, like an airplane. The rest of the road trip was fine because it was mostly highway driving, but whenever I have to have the wheel turned hard right or left, it feels like you're driving through a river, it needs lots of gas to move, like I'm pulling another car or something. This happens at speed too, I have to make a u-turn on a two-lane divided highway to get into my driveway and when I performed it to return home it's as if the truck had drove into a mud pit. Almost came to a dead stop before i gave it some serious gas to get it going again.

Sorry for the long post...Bottom line, could one of my new hub bearings be bad already...and if it is, why does it bog the car down so much only during very sharp turns? (BTW, these are the $33 hub bearings commonly found on e-bay). Could this be a rapidly failing drivers side CV shaft? The symptoms seem to point to this. Maybe with me replacing the hub bearings, I somehow manage to accelerate its demise? I did make a point to look at the boots while I had everything apart and there were no signs of cracks or leaked out grease.

Any help or experience in this matter would greatly be appreciated. Thanks!

Mark

 

Well I definetly don't reccommend cheapo hubs lol. It sounds like your calipers are binding on you. Did you grease the slide pins? Are your wheels very hot? Can you smell brakes? Did you torque the hubs correctly?

 

I'm usually not one for cheapo parts...but the Blazer is a spare car for us. Just use it to haul the dogs to the park and back and sometimes a road trip if we're going mountain biking or tailgating. I put at best 2k miles on it a year. I figured the cheapo hubs would be fine on it for a couple years at the rate I drive it, and it couldn't possibly be any worse than the bad one I replaced.

I didn't have a torque wrench when I put the axle nut back on, I can always borrow one this weekend and check the torque.

I definitely greased the slide pins when i reinstalled the brakes.

Why would I get about 100 miles of trouble free driving and then all of a sudden develop caliper binding, vibration, and airplane like noise?

The wheels aren't necessarily very hot...it is summer though. I did smell the brakes only after I parked the car during my road trip. I figured it was due to the new pads getting worn in a bit. I've smelt it in all my other cars that I put new brake pads on.

 

Classic symptom of a faulty vacuum switch on the transfer case. The vacuum switch leaks vacuum past the seal and applies the front axle actuator which engages the front differential. The "airplane" noise is the axle clutch partially engaging the axle shaft. What you're feeling is called "crow hop", the front axles bind up on a hard turn.



The switch is located on the driver side of the transfer case, slightly above and inboard of the front driveshaft yoke. The part is under $20 at most automotive stores and takes less than 15 minutes to replace it. Dorman Help! 49315 - Transfer Case Switch | O'Reilly Auto Parts

You can see the switch in the image below, just inboard of the encoder motor.