I have a 4WD and wondered if this test will work. Take a long drive to be sure the hub bearings are fully warmed up. Use a IR hand held thermal gun to see check the temp of each bearing hub. I would think if the temperature of one or more hub is much higher that the others, that indicates a bad bearing hub. Correct? The higher friction in that hub is caused by bad bearing.

I have always had problems trying to differentiate between bad wheel bearing and bad/ separated tires. In the early stages, they both --to me--- make the same humming noise.

 

Don't let this job intimidate you. This is actually a very simple job and mainly it's just the right tools needed. There's a big honking nut that I just bought the socket for on Amazon and a breaker bar. It will be worth it to do yourself.

 

When a bearing is unloaded on a turn, it usually quiets down. Each hub has 2 sets of ball bearings, and on a turn, one set on each side is loaded, and one set on each side is unloaded. For example: On a right turn, the left outer and right inner bearings are loaded. The left inner and right outer bearings are unloaded. This can make diagnosis difficult, and could explain why they want to replace both hubs, (they want to make sure the problem is fixed). Bearings can easily be checked using a stethoscope. Remove the wheel, spin it by hand, and listen to the hub.

 

I still haven't gotten around to doing this job, been busy busy busy, but I did buy a pair of quality hubs that were on sale. What size socket did you purchase for that big honking nut? It would be nice to have everything I need before I start taking my wheels apart, lol

Thank you for your response. I wasn't dissing the mechanic, it's a local place I generally bring my vehicles to that treats me fairly. Like I said $800 was just more than I can afford for a job that will take me a couple of hours (total for both tires) at a fraction of the cost. I'll try the stethoscope thing, half my family are in medicine, I have plenty just lying around here, ha.

 

Your local auto parts store will "rent" you that socket with their loan-a-tool program. At least my AutoZone will...

 

Just wanted to state that in my initial reply I was incorrect regarding what sie bearing is bad when making a turn...I said it backwards....I gotta re-read what I type BEFORE hitting post.....


Anyways the socket size is 36mm.

 

Not a mechanic, but I try to take care of my 2003 5-sp Blazer Extreme as best I can. It' got a mild roar coming from the front right side, I think it's probably the wheel bearings. Bought the GM service manuals shortly after purchasing the car. It instructs me to "remove the dust cap". I have no idea how to get the thing off. You-tube videos show other arrangements, which I could open with a screwdriver or GM tool. This is a smooth piece, with almost no gap at all. Is it a sealed deal? Can't get to the bearings until I get past this thing!

 

There's no lip, or ridge, or anything. How could the actual service manual omit so much information? I should have saved lots of $ and bought a Chilton's instead, I think.

 

There is no dust cap. On 2003 rear wheel drive, it's a one piece hub & bearing assembly. The caliper, caliper bracket & rotor must be removed to replace the hub assembly. There are 3 bolts on the inboard side that go through the steering knuckle and into the hub assembly. Here is an image of the assembly:

 

Now that makes sense. I noticed those three inboard bolts, but I didn't make the connection. So much for the gospel of the service manual! Thanks much.