can front wheel bearings be damaged

"N8N" > wrote in message news:9e15667e-1dd9-> >>> Anyone
who thinks that a car can hit a very large and deep pothole and
> >>> not damage something is probably not the most reliable source of
> >>> information anyway.

Of course, potholes can put a lot of stress into many suspension areas.
I have never seen a wheel bearing problem that I could trace back to
that, but maybe it happens.

More than that, some of the early unibody cars, and apparently some of
the later ones, can be bent badly enough by this that alignment can become
difficult. But that has nothing really to do with the wheel bearing
scenario.

My daughter's rice rocket was bent so badly that one mechanic passed
on the alignment, and I took it to a frame shop so that it could be
massaged back into range so that it could be aligned.

On 12/06/2010 12:11 PM, N8N wrote:
> On Dec 6, 2:29�pm, jim > wrote:
>> On 12/06/2010 11:11 AM, John S. wrote:
>>
>>
>>
>>
>>
>>> On Dec 6, 1:24 pm, > �wrote:
>>>> On Dec 6, 12:29 pm, "John > �wrote:
>>
>>>>> On Nov 30, 5:17 pm, > �wrote:
>>
>>>>>> ...by mounting or rotating tires? I don't see how, BUT keep reading.
>>
>>>>>> At my last oil change, I got new tires installed on my company car. I
>>>>>> immediately noticed an increase in road noise, but chalked it up to
>>>>>> the different tread of the new tires (Uniroyal Tiger Paw vs. Goodyear
>>>>>> Integrity) and since the old, OEM tires were so awful, I figured it
>>>>>> was a small price to pay for actual traction.
>>
>>>>>> I just got an oil change again last week, about 7K miles later. I
>>>>>> asked that the tires be rotated and balanced while there because the
>>>>>> car is a notorious tire eater ('08 Impala.) When I got the car back
>>>>>> the mechanic said that I should take the car to the dealership and see
>>>>>> if they would warranty the front wheel bearings because both felt
>>>>>> loose, and he said that typically one should see no perceptible play
>>>>>> in them. I ASSume that these are not the tapered rollers that I know
>>>>>> and love but are one piece cartridge bearings so no adjustment is
>>>>>> possible. I had to take the car to the dealer anyway to get a
>>>>>> malfunctioning door lock fixed (fleet people wouldn't let regular
>>>>>> garage fix it for reasons unknown to me...) and they replaced both
>>>>>> front wheel bearings under warranty and immediately I noticed a
>>>>>> reduction in road noise.
>>
>>>>>> Now, I can't think of a mechanism by which simply undoing and redoing
>>>>>> the lugs would cause a wheel bearing to fail... right?
>>
>>>>>> I suppose it is possible that they just went bad right about that
>>>>>> time... I remember I had one get really loud on the last Imp that I
>>>>>> had but that was maybe 20K miles later (60K vs. 40K miles) funny thing
>>>>>> was that not three days after I had it replaced I hit a very large and
>>>>>> deep pothole at speed and trashed it *again* - wow, they're not real
>>>>>> strong are they? (I saw the pothole but thought it was a patch so
>>>>>> didn't swerve around it) but anyway, it just seems odd to me that they
>>>>>> would both go bad exactly as I had the tires replaced...
>>
>>>>>> nate
>>
>>>>> I don't see how a mechanic could damage the wheel bearings
>>>>> unintentionally. I think that by replacing worn noisy hard riding
>>>>> used tires with soft riding quiet new tires that the sound of grinding
>>>>> bearings was no longer buried in ambient noise and became more
>>>>> apparent.
>>
>>>>> Anyone who thinks that a car can hit a very large and deep pothole and
>>>>> not damage something is probably not the most reliable source of
>>>>> information anyway.
>>
>>>> ??? I grew up in western PA. Hitting large and deep potholes is a
>>>> daily occurrance there, or at least was in the 70's and 80's. Most of
>>>> the time you could avoid them, but sometimes there were just so damn
>>>> many of them that you couldn't avoid hitting one or two.
>>
>>>> nate- Hide quoted text -
>>
>>>> - Show quoted text -
>>
>>> Re-read the OP. �He hit a very large and deep pothole at speed.
>>> Granted, for him at speed might be 5 mph and the pothole might be 2" x
>>> 1/4", but probably all the numbers are much higher.
>>
>> he /is/ the op.
>>
>> and while it's highly unlikely and only really possible if the bearing
>> is either defective or badly under-spec, it /is/ technically possible to
>> brinell a bearing like this. �if the bump is within the range of
>> suspension travel, load would not be high enough to do it, but if the
>> suspension and tire had bottomed, then you could get a high load
>> transient several times the normal running load, and a low spec or low
>> hardness bearing could brinell at that point. �much like bearings
>> commonly brinell when being abused by techs with hammers.
>
> It might have bottomed, the suspension on the car is stupid soft, but
> I kind of doubt it seeing as I was doing about 55-60 MPH at the time
> (onramp.) On the flip side, it was the LF wheel that hit the hole, so
> that side was more loaded than normal at the time.
>
> I just don't remember having these kind of issues with the cars my
> parents drove, which typically only got the bearings packed/replaced
> when the brakes were done, and the brake service intervals for those
> cars tended to be very long as my parents were typically not
> aggressive drivers and the family cars were usually stickshifts. Upon
> reflection, since the late 80's their regular daily use car was a VW
> Golf which also had cartridge-type front wheel bearings, and if they
> were ever replaced on that car, I don't remember it.

double row angular ball. the failures i've seen are usually associated
with technician abuse such as pounding out a sticky driveshaft with a
hammer rather than using a press that pushes against the hub without
loading the bearings.


> I do recall
> having a bad *rear* wheel bearing on that car, which were traditional
> tapered rollers, but those seem to have been undersized for the
> application as I also had problems with them on my own '84 GTI as well
> and have heard the same from others.
>
> nate

often it's caused by "excessive maintenance". in the old days, bearing
seals and greases were poor, so regular re-packing was required. that
practice has stuck through today [much like 3k mile oil changes], even
though it's usually no longer necessary. thus bearings get
over-preloaded, under-preloaded and contaminated from dirty fingers.
bearing hygiene is absolutely critical, and replication of factory
cleanliness almost impossible to achieve.

and as i said up thread, if not loaded within angular range, a roller
element can be loaded on one end and it will wobble in the race causing
it to become barrel-shaped and then further oscillate as it rolls. very
noisy.


--
nomina rutrum rutrum