wheel bearings, noise differnces Options

[tomh]

I have noticed on this forum their is debate over the sound of a rear wheel bearing thats failing.I have a high pitch squeel thats cycilcal and starts at around 30 mph,it will stop with a quick jerk of the wheel to the left.It is not brake related because braking will not affect the noise.I just changed the front bearings and am still hearing the noise.This leads me think its the rear bearings.I have read all the past threads on this subject and some people say bearings only growl when failing.My question is it possible that this high pitch squeel could be the bearing?

[Cap'n Krusty]

Not very likely.

The Cap'n

[cary]

I had on fail on my 911. No squeal. It was a harmonic drone.

[wertygrog]

Yep, mine did the same exact thing. The squeel would vary up and down in pitch with wheel speed, and would stop shortly before I would come to a stop. It was the drivers side rear bearing. I replaced it (it turned out to be very pitted), and the noise went away. Now 2 years later, the noise is starting to come back on the passenger's side, so it's time to tackle the other rear bearing.

[SirAndy]

No squeal. It was a harmonic drone.

(IMG:style_emoticons/default/agree.gif)

It's usually a low pitch "grinding" noise, sometimes you can feel the vibration through the chassis.


But i wouldn't discount the bearings completely in your case. They are cheap enough and they are a wear item.
If you don't know the last time they were replaced, you might as well. For all you know, they could be 40 years old ...

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[Elliot Cannon]

Could it be cv joints?

[stugray]

"Could it be cv joints?"

IME, the symptom of CVs going bad is a popping noise, that usually occurs when cornering.

However, a GOOD CV that has lost all of it's lubricant might whine.
Check to see if the boots are all intact.

Stu

[detoxcowboy]

could be the front again, shit happens.. find a long wall somewhre and drive next to it with the window down to help you pinpoint the sound.. last itme i had a little squeky sound it was the alt.. before that front wheel bearings.. play with it different scenarios until you can affirm that you can make it happen and make it stop.. or not.. does it squek only while moving ?

[astronomerdave]

I have what seems like the same problem. Never below about 25-30 mph but usually on the freeway I hear a periodic high pitch squeal. Imagine a hamster wheel that needs oiling (swheee swheee swheee ...). In my case it sounds like it's coming from the rear of the car, rather than the front.

Also not brakes, as it persists when brakes applied, released.

Clutch in, out,
in gear, out of gear,
motor on, off,
combinations of above,
still squealing.

Also not CVs as I heard it before and after replacing all four CV joints. I deferred investigation until I finished the CVs. Now they are all new. What's left but the bearings?

[6freak]

My question is it possible that this high pitch squeel could be the bearing?

simple put YES it can generate a frequency that is like a squeel

[pcar916]

I'm not gonna speculate, but instead put in a plug for Preventive Maintenance, otherwise known as "PM". Industry and racing concerns rely on it to keep costs down and safety at a predictable level.

That's when, at regular intervals, you inspect and repack the CV's and wheel bearings. PM isn't limited to these items of course. But I've never had either one give me a catastrophic problem.

Every two years (street car) or every year (street/track car) or every few races, wheel bearings get inspected and repacked with synthetic grease. No dino grease here, synthetic is the best for bearings because it's slippery... er. Given proper maintenance CV's go longer than bearings, but are one of the most neglected high-wear bits on our cars. I'd take all of the above pieces out for a PM session, replace what's pitted and repack the rest. Then write down what you did and when.

Do it again before you have a problem.

Note: PM is one of the first things to go when the budget gets tight, for government, companies, and people. It's a false economy and costs more in the long run. I understand when it happens but it's gonna cost more in the long run.

If you have a problem with one bearing/cv then you may have one with the others if they've been treated in a similar fashion so inspect them all.

Heck, some burgers and a little beer will attract all kinds of interested 914'ers to help!

Good luck finding your squeal. I'd make no assumptions.

Tech tip: With tapered bearings slightly loose is better than slightly tight... and loose bearings rumble

[tomh]

I went ahead and changed all 4 bearings front and back and the noise stopped,I had truble telling what corner of the car it came from so I just changed all of them.

Major PINA!

[Eric_Shea]

The special bearings they use on 914S models cause a "squeal"... just say'n. (IMG:style_emoticons/default/wink.gif)

[timofly]

I have what seems like the same problem. Never below about 25-30 mph but usually on the freeway I hear a periodic high pitch squeal. Imagine a hamster wheel that needs oiling (swheee swheee swheee ...). In my case it sounds like it's coming from the rear of the car, rather than the front.

Also not brakes, as it persists when brakes applied, released.

Clutch in, out,
in gear, out of gear,
motor on, off,
combinations of above,
still squealing.

Also not CVs as I heard it before and after replacing all four CV joints. I deferred investigation until I finished the CVs. Now they are all new. What's left but the bearings?

I had the same exact problem and it was rear wheel bearing. The really weird part was that you could jack the car and do whatever you wanted to that wheel and it just seemed solid as a rock: no grinding, no wobble, no movement. But it was the bearing.