donbrew

A. if the wheels are off the only thing keeping the rotors on is the calipers. Noise vibration.
B the test for hub/bearings is end play/runout .005 inch. But, if they are that loud you can probably feel it with wheels on. (that is 5 thousandth)

DrLoch

Bad hub sounds are difficult to pinpoint from inside the car. Wifes POS saturn had a bad left front hub when she brought it down to NC. I of course buy 2 knowing that the other is not far behind, as luck would have I didn't get two of the same part number hubs from Rockauto, shipping/packaging mistake.... anyways I replace the bad left front hub noise goes away ABS light is out all is good with the world except I was only able to replaced one. Long story short, the other hub went out about 2 weeks ago but from inside the car it's very difficult to hear where the noise is coming from. If I hadn't know better I would have thought is was the left front not the right front.

Mac-101

A big shout out to Whopper, Donbrew, Doc Brown and Dr Loach. I just got done replacing the wheel bearing and new brake pads. The wheel bearing really had no play except when out it did NOT move smoothly when rotated by hand. The CV Axle acted like it was goin to be a be a rear Bear so I skipped it since I saw the binding in the wheel bearing. So I got off with under 100 bucks and ONE Hour and it went up to 70 mph real smooth. I WILL replace the other wheel bearing and brake pads this week end.
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Evidently the vibration from the worn/binding wheel bearing traveled through the outer to the inner CV Axel joint and manifested it's self as a noise where the tranny and C axel connect.
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Once again thank you so much for your help. Also, I was amassed how easy THEY made it to change the wheel bearing and disk brakes in the 21st century compared to the 20th century cars and trucks I usually work on.
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DrLoch

I too have felt a vibration in the steering wheel when the hub was bad. Both felt like they had square ball bearing in them.

Mac-101

Dr Loach; This weekend after I replace right side wheel hub I'll be interested in seein if my mileage goes up form 29/31 mpg to more like mu Cobalt at 35/7 mpg. I'll let you'll know come next Wednesday.

Doc brown

Mac that's not likely. The high roof creates more wind resistance than the Cobalt does. A bad wheel hub won't reduce mileage at any significant amount.

Oldblue

Mac-101

Thanks Ole Blue. Doc, I believe the HHR is 500 pounds more than the Cobalt and has signicantly more wind resistance. In addition I believe the gears are lower on the HHR. However, when I spun the wheel bearing by hand once it was off, there was major resistance in it's spinning and you could feel it catching constantly on the worn bearings. So I hoped to git a little moe out of it. I just got 28 mph on a trip doin a lot of 60 to 70s mph! I usually go between 55 to 60 on country roads to git he better mileage. SO it most likely hasn't changed of any significance.