Whats a failed wheel bearing sound like?

[mikesride]

Hunting down a hollow "clunking" sound in my right rear suspension and have found nothing. Can a failed rear bearing cause such a noise? Its not constant, suspension travel or road conditions seem to have no effect on it. I don't want to drive it until I can figure this out. Its a stock suspension 82 sc.
Thanks

[widgeon13]

Don't think it would be a clunking sound, more like a growl as the speed increases the sound might get louder and tone will change with speed. Check that all lug nuts are tight and torqued properly.

Could also be a brake pad issue.

[Joe Bob]

Possible CV joint....

[Bob Kontak]

Not an expert but referencing Job Bob's thoughts, double check the tightness of the CV joint bolts. If loose, search on CV bolt joints and do what Grady Clay says.

[Walt Fricke]

I just went through this. Things mostly normal when driving in a straight line, but turning either way produced a noise, though I wouldn't call it a clunking.

Bit the bullet and pulled one side's CVs. They were OK. Pulled the wheel bearing (a much harder task than CVs). Oh, it was fine but I replaced it.

No change in noise.

Pulled axle on other side, found one CV which had a little damage. Enough to replace, but didn't seem like it would cause the symptoms. Put back together with a new CV. Alas, same noise.

The bearing on that side, when removed, did not require an expert to see that it was the culprit, and replacement brought normal driving.

What fooled me is that 1) this bearing had been replaced in about 1989, so I thought it was fairly new, and 2) with the first bearing replacement the symptom was noise on hard right hand cornering (when the left side bearing was most heavily loaded), and none on hard lefts, at least not that I noticed. This time there didn't seem to be much side to side variation.

However, I've had failing CVs produce noise differentially depending on which way I was turning.

Short answer: pull both axles and inspect the CVs. My rule of thumb is almost just that - if I can feel any grooving of the races with a finger, replacement is in order. Areas which are shinier than others, and more polished, are normal and just fine. Grooving is not. And when you see irregular pitting, that might well be the source of noise.

If your CVs are OK, or after replacing those which are not OK, you still have the same noise, you are faced with pulling the bearings. There are posts right here on how to do that at home, and how to fabricate some low cost tools to help.

By the way, Porsche and the books all say that once you pull the hub (the part with the wheel studs in it), you have destroyed the bearing and need to replace it. I no longer believe this. If the bearing is in good shape, you can just pull the outermost inner race (which comes off with the hub) off the hub, put it back into place in the bearing, and press the grease shield back with your fingers into its retaining slot and you should be good to go. you could always add a little more grease if you wanted. Pulling the bearing with heat and a puller shouldn't damage balls or races. Pounding things apart with a big hammer, though, might. That is how the factory shows it being done, but I used my PortaPower hydraulic system to push the hub out, so no impacts.