Hub bearing failing?

[choccibicci]

My 540's front o/s wheel is getting very hot, too hot to touch after 10 mins driving. Is the bearing failing? What else could make it get hot?!

There is no wobble, or vibration, though which is odd.

Are the e34's bearings built into the hub, making for a new hub as opposed to replacing the bearing?

Ta

[DaveVoorhis]

Dragging brake caliper, maybe?

[Dave M]

I would suspect a grabbing front brake caliper far sooner than the bearing, unless you're hearing nasty noises. Raise the front wheel and check for resistance. Try this before the next time you drive it. If you're not sure whether you're feeling resistance, check it with the wheel removed. Aslo inspect the disc as you may see some glazing or other tell-tale signs, depending on how long it has been occuring (compare it to the other disc).

Yes, the bearing is integrated into the hub assembly.

http://img.photobucket.com/albums/v11/dave_macisaac/hub.jpg

Real.oem lists @$200 for the hub, while theBMA Site (http://catalog.bmaparts.com/epcvsoapimc.epc?cookieID=1F11DVXLK1ZK0SG7GU&drillid=8&subcatid=801030@@Front+Discs+%26+Drums&source=BIMMERINFO&clientid=bmaparts) lists b/w @$100 to $130 (FAG or Meyle).

Good Luck with it,

Dave M

[scott 4991]

How did you notice this wheel getting hot? Did you stop and see smoke? Feel it dragging when you were driving? or other?

Thanks

sc

[choccibicci]

I swapped my wheels around (rears to the front) and noticed one was a little low on air. Drove to the garage to pump it up with no drama's.
About a mile up the road there was a slight wobble, almost like running on a flat so I pulled over - nothing, but the wheel was incredibly hot.
Luckily, I wasnt too far from home so I carefully made it back, but the wobble had gone away! I've never had any wobbles from the car before so thought it a bit odd.

There wasn't any resistance when I swapped the wheels around, but i'll check again tomorrow.

Wheels are 17" momo on 235/45 continental tyres, unmodified suspension.

[Podmore]

Bearing failure will usually present as a slight rumbling or grinding noise, possibly exacerbated when cornering as the bearing gets loaded up. It won't cause excessive heating in the wheel unless it's virtually seized. Check with the car up on a jack and grab the top and bottom of the wheel, try to wobble it and check for excessive movement or clicking.
Most likely a brake caliper piston sticking in the bore - the "wobble" that went away is curious - pull the suspect caliper off and push the pistons back into the bores (make sure you don't have an over-full brake fluid reservoir before you do this) - a large "C" clamp is useful for this job -and then - keeping the pads in place to prevent the pistons from popping right out, get a mate to gently push the brake pedal down a few times to get the pistons to extend, then push them back in again. Generally solves the problem.

[Qube]

Suspect brake dragging. Prop the front and spin the wheel. Feel higher resistance on one side?