humming noise after hitting curb

Long story... kid walked out in front of me, had to swerve around idiotic "traffic control device between lanes", ended up fishtailing and hitting curb with drivers front wheel at about 10 mph. I am willing to admit that I am not completely free of blame (could have driven over traffic device, accelerated out of fish tailing, etc). No apparent damage to the aluminum wheel, fortunately. I tried to check the alignment while coasting on the highway, doesn't seem terrible, but there is a pull to the left in the left lane with absolutely no pull in the right lane (I assume this means there is a slight pull to the left which is accentuated by the crown in the left lane, but canceled in the right). I don't feel any vibration, although immediately after hitting the curve, I thought it felt like I could have had a flat (lots of crap running around my head though). Now I notice a humming noise which appears intermittently, or more likely under specific conditions, for example: driving at highway speed the sound cycles at about

1 Hz; when coasting to a stop it occurs constantly, but changes pitch with speed like a decelerating engine/transmission. It also seems, although it could be my imagination, that the car decelerates more when coasting. The car is a 93 Oldsmobile Cutlass Supreme with 3.1 L engine 130,000 miles. Any ideas what the noise is a symptom of? I'm trying to think of what things this incident could cause or a nearly worn part that this could cause to fail. My ideas are a bearing, CV joint, tie rod, half shaft (is this the correct term)?

Side note: I replaced front rotors last week; in the past I had a problem with not tightening the bracket bolts tight enough, but this time I used a torque wrench.

Thanks for any insight anybody can provide.

Reply to
Andrew Sasak
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I'd take a guess at a "bruised" tire - I imagine the curb-shot did at least some damage to the tire - perhaps "dinged" one of the belts, caused a soft spot that has "bubbled", putting the tire out of round enough to make a noise as it rolls, or similar.

Legal or not, wise or not, I'd be looking for a nice smooth clear spot to do some checking...

Get moving as fast as your clear spot allows, then pull it out of gear and coast - Does the noise still occur? If so, you've just ruled out tranny problems, and probably (but not certainly) driveshaft/half shaft related issues in the process.

If that test comes up with no useful answer, swap the tires front to rear. Any change?

What about steering vibration? If the tire has a messed up belt, chances are high that you're going to notice *A LOT* of vibration in the steering - If messed up bad enough, it's easy to get the idea that the car is about to shake itself apart. A minor belt injury might take some time to "develop" to the point where the vibration becomes a problem.

Reply to
Don Bruder

(snip)

Humming noises are frequently bearings. With the milage on that car you might want to check them anyways.

Reply to
« Paul »

I have a '90 Cutlass Supreme. When my front bearing was going bad (which can be "accelerated" by hitting a curb), I noticed a humming noise too, but only while I was turning. It didn't make much noise at all when going straight though. A new bearing kit cost $100 and I replaced it myself, it's a sealed unit. -PapaRick

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« Paul » wrote:

Reply to
Rick Colombo

How do you check them? I didn't see anything in my service manual about checking them, I guess I'll have to look again when I'm back at my parents'. If it is the bearing, I assume it being bad causes increased friction, which in turn lowers mileage and creates heat which could affect the brakes. It seems like one way of checking would be to see if my drivers wheel is considerably warmer then my passengers after a sufficiently long trip. Thanks for your reply.

Reply to
Andrew Sasak

Check for noise, runout, slop, crunching during slow turning by hand. You could disassemble them and look for worn or flat spots. Probably NO noticible increased friction until the wheel falls off.

Reply to
« Paul »

Since the vehicle is front wheel drive, how exactly do you suggest turning the bearing by hand? With both wheels off the ground? With both sides off ground and wheel removed? Or completely removing the bearing? It seems that the differential adds an unknown to the equation.

Reply to
Andrew Sasak

Jack up one corner, put the trans in anything but park, and turn the wheel. There is not a lot of resistance and you should still be able to "feel" a bad bearing. Don't confuse it with a bad cv bearing. They tend to be somewhat similar at times but the cv should make more noise under strain. The best way would be to take it all apart and inspect each piece. Unfortunately, that can't be done much anymore.

Reply to
«»

I jacked the wheel up and turned it both by hand, and by engine (suggested for diagnosing bearing in service manual). I compared both sides, since I have never tried this sort of diagnosis before. The only thing I noticed was some slop when changing directions when spinning by hand, which seemed to be noticeably worse on the drivers side. When spinning the wheel with the engine, I noticed what seemed to be the original suspicious noise, as well as vibration, above 20 mph or so. This seems to be very possibly a bad bearing, however not being able to notice anything significant by hand spinning makes me wonder if it could actually be an out of balance tire/wheel. I'm a little reluctant to replace a $100 bearing without being sure that it is the culprit, but I suppose that its probably a good time to replace it anyway. The other side was replaced about a year ago. Any more advice you provide, given these added observations. Thanks for all your help.

Reply to
Andrew Sasak

If you lifted the car by the frame, then the drive shaft was at =

a pretty good angle. A noise then would more likely be cv joint. That also fits with the vibration. Bad bearings tend to make more noise when they have to support the weight of the car plus stopping or turning force.

Reply to
« Paul »

I lifted the wheel by the lower control arm, not the frame. I assume that nullifies your comments? Does this make it more likely to be a bearing. I really want to figure this out, I'm going to need to drive me car, and I don't want the wheel to fall off.

If you lifted the car by the frame, then the drive shaft was at a pretty good angle. A noise then would more likely be cv joint. That also fits with the vibration. Bad bearings tend to make more noise when they have to support the weight of the car plus stopping or turning force.

Reply to
Andrew Sasak

Not necessarily but does make it more likely it's the bearing. Replace the grease seal and big nut when you do the hub.

Reply to
« Paul »

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