jjdamien

Just today my 00 S4 started to make a humming noise that got higher pitched with acceleration but was independent of the cars RPM's. After some research I've concluded that its one or both of the rear wheel bearings that need replacement. I plan on replacing them both ASAP but tomorrow I'm supposed to be taking a trip 200 miles each way. Is this something that needs to be replaced immediately to the point that I can't take the trip in my car tomorrow, or can i just ignore the hum until I get back on monday??
Thanks again

complacentsee

Usually it is no big deal to drive on a wheel bearing thats going out. They just progressivly get worse and worse. I don't know what happens when they completely fail. I had a friend put on 5k-10k miles on one that was going out. Sounded rediculous when he finally replaced it. (B5 A4, quattro) I wouldn't recommend doing as he did. Just get it replaced as soon as you can.

audikidS4

I've been rolling on a noisy wheel bearing for like 6 mos now...Just don't let it go forever, esp. if it get real loud...

shawnoc2003

Hard to say when a wheel bearing is actually going to fail completely, but the fact that your getting noise is pretty serious. The last one I had to replace started making noise and <100miles later I barely made it home. By the time I got home, I could rock the wheel back and forth on the axle. Not sure if it would have fell off, but it sure felt like it.

For what its worth, I'd rent a car - probably cheaper than getting towed to a dealer you don't know.

sbs43000

yeah i've replaced both rear bearings on my 00 S4. The first one i probably waited about 6 months. My mechanic said it was completely shot when he took it off...basically fell apart when he took the wheel off. The second one I only went about a month or so on. it got bad more quickly than the first. That noise drove the crap out of me, but i've definitely drive on bad wheel bearings up to 6 months without my wheel falling off or ceasing up.

Is that what happens when it completely fails, The wheel just locks up and won't turn? I would imagine that could cause damage elsewhere.

complacentsee

I tried to figure out what would happen when I did mine. From what I could tell if the bearing completly goes, the CV will end up grinding and slamming into the upright. Wheel wont fall off, but damage could occure to all but not limited to the CV joint, upright and hub. Possible damge to: suspension components, wheels, tires, rotors, calipers, and brake lines.

shawnoc2003

I actually reached a point where you could feel the wheel push in when I turn right (the noise would also go away) and then push out when I turned left. - the driver rear bearing was going -.

Suffice it to say, even though the rear axle bolt holds the CV joint into the wheel, at normal highway speed I wouldn't be surprised if the bolt just snapped and the wheel took off. At some point, as the bearing races seperate, there is going to be severe moment loads put on the bolt.

Of course if the wheel were to come off, I probably would have spun out and hit something which would have taken care of needing to replace the wheel bearing.

donromani

From what I recall the biggest risk is that the bearing seizes and the wheel essentially torques the entire wheel assembly right out of its anchor bolts....So yeh, I would do it sooner rather than later.

complacentsee

"wheel assembly" = upright? "anchor bolts" = control arms? or WTF are you talking about?

donromani

Sigh...you damn nomenclature ****. Wheel assembly = the whole fvcking thing, everything from the upright to the rotor, the entire "assembly" as it were. Anchor bolts = the bolts connecting the housing for the shock absorber to the frame (and yes, the upper control arms are attached to this housing).

Is that better, mein Fuehrer?