kazoo sound from wheel bearing? odd..

'85 BMW 318.

When I swapped in the rear suspension/brakes from a 325i, I noticed that one of the rear bearings made a wierd "kazoo" noise (like the kids toy), when spun in a forward direction. This was before the axle, brakes, or anything else was installed. It did not make the noise when spun counter-clockwise. It spun freely and smoothly, but just with that wierd noise.

I went ahead and used it, thinking that once everything was assembled it would be fine. And it was noise-free for all my local driving, long trip to Sumiit, the rallycross, drive home, etc.

Then today when test-driving with the new steering rack, it came back. Same kazoo sound that got louder when driving faster. Then I stopped, put it in reverse and backed up 5 feet. No noise. Then went forward again, and drove the rest of the way home. No noise. Put the back of the car up and no sign of bearing wobble, grinding, or any other typical bearing issues.

I've had some bad bearings on other cars and always get the whirr/howl/grind sounds. I've never heard THIS sound coming from any car, ever. I mean, seriously, it sounds just like a kazoo. Almost like it's caused by air getting in there and causing the noise (or like when you put a piece of grass or paper between your palms and blow through it.

Any insights?

Why not just replace it? That would make me really nervous.

mostly because replacing rear wheel bearings on an e30 is perhaps the biggest PITA in the world. And I want to figure out if it is actually a problem, or if it is just some wierd resonance from something.

Nothing to add except I just learned that kazoos are supode to be kids toys. :D

Place a slide hammer puller through the rear bearing. Heat up the outside carrier nice and HOT with a torch, a couple good hits and it should slide right out. To put one back in, put the new bearing in a freezer couple hours. Heat up the carrier nice and HOT, should slide in relatively easy, if it hangs up a bit, us a couple large washers or a large socket to tap it in on the outside race. Do not put pressure on the inside race, will mess it up.

My 2-pc driveshaft uses a center carrier bearing. When it's cold out, it can sometimes 'sing' - a high frequency whining sound that varies with speed.

I'd be a little concerned about your sound, because it seems like it's much closer to turning into a grumble/growl. It may just be telegraphing the early signs of impending failure.

Was it making the kazoo noise when turning the wheel by hand? Same pitch as when you were driving it, or does the pitch change with wheel speed?

Only forward and not backwards makes me wonder whether it's a bearing or possibly something else. Then again, if it's a cage failing, most of the wear will be on one side of the roller pockets because you spend the vast majority of your time driving forward - I do anyway.

Cage failures most often trace back to lack/wrong type/contamination of the grease. You may not get the loud GRRRRRRRRRRRR or WAHWAHWAHWAHWAH noises you get from an inner or outer race spall unless there's damage to a roller.

Mind you, I'm not completely convinced it's a bearing fault yet.

find someone who can lend u a "hubtamer" youll be done with that bearing is such short time u wont have finished your first drink.

akamcfly wrote: Was it making the kazoo noise when turning the wheel by hand? Same pitch as when you were driving it, or does the pitch change with wheel speed? Only forward and not backwards makes me wonder whether it's a bearing or possibly something else. Then again, if it's a cage failing, most of the wear will be on one side of the roller pockets because you spend the vast majority of your time driving forward - I do anyway. Cage failures most often trace back to lack/wrong type/contamination of the grease. You may not get the loud GRRRRRRRRRRRR or WAHWAHWAHWAHWAH noises you get from an inner or outer race spall unless there's damage to a roller. Mind you, I'm not completely convinced it's a bearing fault yet.

since I have an LSD rear, it's pretty hard to turn the wheel fast by hand, not fast enough to make that sound. Before I attached the axles I could make that sound spinning the hub by had (before I had put on the brakes or anything else). I didn't feel any resistance, or grinding, or any of the usual bearing failure symptons. In fact it was arguably smoother than the quiet bearing on the other side, as I recall (hence why I didn't change it then and there).

In any case, it's annoying so I'll probably change it out in the very near future. 4 weeks until the next rallycross so I have time to do that.

Also, it's like a musical chorus from the right rear corner, since my fuel lifter pump (in-tank) is humming up a storm as well

irish44j wrote: since I have an LSD rear, it's pretty hard to turn the wheel fast by hand, not fast enough to make that sound. Before I attached the axles I could make that sound spinning the hub by had (before I had put on the brakes or anything else). I didn't feel any resistance, or grinding, or any of the usual bearing failure symptons. In fact it was arguably smoother than the quiet bearing on the other side, as I recall (hence why I didn't change it then and there). In any case, it's annoying so I'll probably change it out in the very near future. 4 weeks until the next rallycross so I have time to do that. Also, it's like a musical chorus from the right rear corner, since my fuel lifter pump (in-tank) is humming up a storm as well

Smoother as in it spins easier? That's not necessarily a good sign. To me that means you may have more clearance/less preload than the other side. A new cartridge bearing will feel more draggy than a worn one. By your description of the noise and feel of the bearing, I don't think you're living on borrowed time yet. But since you have a decent time window and it's a race car, you might as well change it now instead of changing it under duress.

thanks....I already ordered a new one.

I don't mind the changing process fo the bearing. But getting the spline shaft of the axle back through again is my nightmare. It too FOREVER the first time I put it together