[ds968]

I realize anything is "possible", but in terms of "probable" is it likely wheel bearings

would start to deteriorate by 75,000 mi ? btw, car has never been tracked

( if that makes any difference.. )

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[Greimann]

It is not uncommon to replace wheel bearings once in the life of a car. If they have been treated well, they should be good into the 100K mile range, but there are so many variables that affect bearing life that a typical mileage life is hard to nail down.



Are you having symptoms of a bearing failure like excessive noise or steering problems?

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[ds968]

No steering problems at all, no vibration of any kind, and as for what might be deemed "excessive" in terms of noise I guess that interpretation varies from

person to person - it's not a terribly loud sound, but it's one I don't recall hearing before; may be it was there and I just did not pay much attention to it.. it's mostly audible around 90 mph and above - at 100, 110 it sounds like a muffled whirrrr accompanied by what I would describe as a howl. Around 120 and above it seems to get QUIETER. I initially thought it's the tires, but now with new tires, while the noise is somewhat improved, it's definitely there.. I can hear it if I pop in in neutral and coast on the highway. I can also hear it at lower speeds but no way nearly as pronounced. Here's what leads me to suspect a bearing: even though it does not get louder when turning either left or right, it does disappear completely for a second or two while making a sharp, sudden right turn ( but does not change with the same sharp turn to the left. )

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[Greimann]

Oh yea, the muffled whirrrr howl. Front wheel bearing for sure. Considering that you broach 140 mph on a daily basis, no wonder <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[ds968]

So if the sound goes away when making a sharp right turn only, is it the left wheel or right wheel bearing ? Left wheel, since there is less load on with a right hand turn ? ( Please forgive the cluelessness of what is undoubtedly the most elemental of physics )



In any event, I HOPE it's a front bearing and not rear ones since I understand they require far less time ( a.k.a. $$ to my mecahnic ) to fix. Is it advisable to

do both wheels, or is it ok to only inspect the other and if it's ok, have it just repacked ?



p.s. 140mph is not daily. it's every other day <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />

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[Greimann]

Replace them both. You want everything up front to be symmetrical. The parts and the job should be relatively inexpensive.

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[ds968]

[quote name='Greimann' date='Jun 5 2005, 08:32 AM']Replace them both. You want everything up front to be symmetrical.

[right][post="5451"]<{POST_SNAPBACK}>[/post][/right][/quote]



makes perfect sense. gracias. <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[ds968]

had the car on the lift, front wheels solid and spinning quietly, same for the left rear wheel... and then... *@#! - it's the right rear wheel bearing causing all the whirring and howling. damn. mechanic indicates 4 hrs labor so not an inexpensive fix, but gotta do it, I suppose. <img src="/forum/images/smilies/968/mad.gif" class="smilie" alt="" />

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[rustech]

I haven't had to do it yet, but supposedly those rear wheel bearings are much harder to replace than the fronts. So in this case, is it important to replace both sides, or just the one since it's the rear?

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[ds968]

according to my mechanic ( and he also promotes the idea of replacing both FRONTS at the same time when you have to do one of them ), the rear does not necessarily call for the same "symmetry" treatment, if the other bearing is tight and quiet.



I was surprised to hear that since the axle and all that other crap has to be disconnected and given the part itself is cheap, I'd think it may save a lot of time and labor in the future by doing that now, but I guess it follows the similar principle guiding opposing opinions on replacing a perfectly functional water pump when you do the belts** .. He says doing one rear bearing is 4 hrs, doing two is 7 hrs, so I'm risking only hour of labor ( $ 90 ) when and IF the other one might go bad.. One of those flip a coin situations I guess.. I'll take a chance and just replace the bad one.



** btw, I had plenty of belts changed on the 944 in 17 years and one change in the 968 two years ago, and left the water pumps alone - never had a problem !

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[ds968]

ahhh... so quiet now after replacing the wheel bearing ...



but there are downsides: the wind noise is even more noticeable than before <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" />

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[Greimann]

[quote name='ds968' date='Jun 9 2005, 10:48 AM']but there are downsides: the wind noise is even more noticeable than before  <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" />

[right][post="5624"]<{POST_SNAPBACK}>[/post][/right][/quote]

And then! Oh, the noise! Oh, the Noise!

Noise! Noise! Noise!

That's one thing he hated! The NOISE!

NOISE! NOISE! NOISE!

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[ds968]

<img src="/forum/images/smilies/968/tongue.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/laugh.gif" class="smilie" alt="" />

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[Brian]

i have a general wheel bearing question. i'm not a master mechanic, so please bear with me...

i was doing some cosmetc repair on my front wheel this week. i had the wheel off and was checking out the brake job a mechanic recently had performed. i spun the rotor a little bit and was surprised how much effort it took to spin the thng. if i spun it as hard as i could, it would not go on it's own at all. is this right? i'm wondering if i need a bearing lube job? or are these not really supposed to be easy to turn? i'm sure the bearings are working fine. no noises or vibrations or anything like that.

even with the wheel on, it still took some effort to spin the wheel.



just curious.

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[Greimann]

That is normal. What you are seeing is pad drag. The brake pads drag ever so slightly across rotor face. When the car is is motion they back off so the drag is much less than what you experienced, because the last thing you did before parking the car is to apply the brakes. If your wheel bearing was too tight or lacked grease, you would know it, as it would have welded itself to the spindle by now.

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[Brian]

thanks greimann. i had no idea that brake pads did that. i was ready to peel the mechanic's head for a bad install job! good thing i asked.

two less things to worry about.

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