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  #1  
Old 06-11-2003, 01:57 PM
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Join Date: Sep 2002
Location: San Francisco Bay Area
Posts: 452
W124 Bearing question....

Hi All,

I seem to be hearing a light "roar" whenever my wheels are rotating while driving. I'm thinking it's the bearings...advice?

If it is the bearings, how hard is it to re-pack? What tools/parts are needed? Instructions?

thanks,
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'87 W124 260E (DD)
98K orig. mi. @7/15
CLK 7-Spoke Forged Wheels
Neuspeed springs/Bilstein Sport
4/3 bump (F/R)

'97 993 Carrera
106K orig. mi.
Always driven like it's stolen
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  #2  
Old 06-11-2003, 02:38 PM
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Join Date: May 2002
Location: Mass
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Could be other things.

Bearing noise will usually change or go away when you turn one way or another.

Bearing problems will eventually show up in uneven tire wear, esp. cupping.

Hub with worn bearing may feel notably hotter than the other side after a fast run.

Bearing that is already growling should be replaced, not repacked. Don't forget to order the grease seals!

The hard part of Front Bearing replacement involves driving out and reinstalling the races. Well, driving out is not that bad, but it helps tremendously to have the right tool for install. I got by for years scrounging together pipes of the proper diameter, carefully working brass punches, using the old races to drive in the new ones, and so forth. Always managed somehow.

Finally got a $50 race install set from Lisle. Not sure why I waited so long... Too cheap, I guess, but what a waste of time!

Still helps a lot to put the races in the freezer before driving them in. Heating the hub is optional. Contraction is a marvelous tool!

Best of luck.
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  #3  
Old 06-11-2003, 03:25 PM
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Location: Dallas, TX
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My father had a similar problem on his '87 300E. It was the left rear bearing. It cost him $350 at an independant shop. Is yours coming from the rear or front? Whatever the outcome please post so that others will know what it was.
David
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  #4  
Old 06-11-2003, 03:32 PM
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Had this noise on my wife's Accord, but it turned out to be a bad tire. No problems evident from looking at it. I pulled the front calipers and disconnected the axle shafts, then spun the hubs. Nada - no noise or roughness at all. All back together, I rotated the tires front/rear, the noise moved from front to back too. New tires, and silence was golden.

Steve
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  #5  
Old 06-11-2003, 04:38 PM
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Join Date: Jun 2002
Location: Motor City, MI
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Good advice above. To add, I've been fooled before by worn brake pads that mimic this roaring you described.

Have you isolated the noise to one corner of the car? If it's one of the front bearings, your problem should be obvious once the bearings are apart.
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  #6  
Old 06-11-2003, 10:07 PM
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bearing woes

HI All,

Great advice and insights.... thanks....

One more thing, what's the best way of testing/isolating this problem i'm having. should I jack the car up and rotate the tires?

thanks again....
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sjsfiji

'87 W124 260E (DD)
98K orig. mi. @7/15
CLK 7-Spoke Forged Wheels
Neuspeed springs/Bilstein Sport
4/3 bump (F/R)

'97 993 Carrera
106K orig. mi.
Always driven like it's stolen
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  #7  
Old 06-11-2003, 10:53 PM
I told you so!
 
Join Date: Jun 2002
Location: Motor City, MI
Posts: 2,791
Unfortunately, there is no good way to isolate this problem. It takes a good ear and a willingness to take the shotgun approach to repair. If you jack the car up, the load pattern on the bearing is changed. Any spall in the load area now doesn't see any load. So that doesn't work.

If you will be repacking the bearings, there are a few rules to follow:

All old grease MUST be washed out of the bearing. Bearing must be dried.

The bearing must be thoroughly examined. If it is less than perfect it must be replaced. Bearings are replaced in sets (inner race, outer race, & rollers). There are two sets per front wheel.

Setting the preload (bearing play) is critical. It must be done right! A dial gauge is the preferred method. But you can get by setting it by hand. To set the preload, tighten the nut snug (~40 ft-lbs) while rotating the bearing by hand. This'll squeeze the excessive grease from the contact surfaces and seat the bearing assembly. Back nut off nut until loose. Then tighten finger tight. Lock the nut. Preload should be good.

Bearings cannot be nicked, scratched, or corroded or the bearing is ruined. Even excessive polish is bad. Anything less than the original hone finish and the bearing is unfit for further use. Bearings cannot be hammered in such a way that the force is transmitted across the rolling contact surfaces.

You should get yourself a manual to learn how the repack a bearing with grease and how to exchange races from the hub.
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  #8  
Old 06-12-2003, 11:09 AM
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"One more thing, what's the best way of testing/isolating this problem i'm having. should I jack the car up and rotate the tires?"

Yes, though if you suspect a particular 'corner' as the source, just rotate that one tire elsewhere. If that is the cause, you'll notice the sound source moved as well. If it is the bearing, you won't.

If a bearing, I have also found it easy to tell off the ground by rotating it. However, the pads must be removed, and axle if a drive wheel. This is also best done if directly compared to a good bearing, e.g. doing the same thing with the one directly across the vehicle.

I once found a bad rear bearing in my Integra (fwd) just while replacing the rear pads. Rotating one felt a tad rougher and swooshier than seemed right. Checking the other side confirmed it. It was not even noisy enough that I had noticed it while driving, but I DID notice something was missing from the sound envelope afterwards (not a real quiet car).

Steve


Steve
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