Wheel Bearings Going Bad Just Sitting There?

[Kestas]

The only way sitting could cause damage is if the seal failed, allowing static corrosion to occur. But even that is a long shot because water would degrade the grease to where the bearing would suffer lube failure.

In our wheel bearing warranty return, the primary reason for early failure is water ingress from a bad seal. There are other reasons, but we are guessing. Only a proper examination would let us know. Never have we found a bearing that failed in warranty because "it sat too long."

 

[Claud]

Originally Posted By: Kamele0N
Originally Posted By: BrocLuno
OK, so the rear end oil level is often below the bearing when sitting level. They get occasionally oiled when you turn or side hill, park on off camber, etc. Ball and roller bearings do not need a lot of oil. But they need a good residual film.


Thats why I put my finger on filling hole when filling rear diff...to slightly "overfill" rear diff.

I really dont know why all manufacturers drill that filling hole to sit just below the driving axle? So that rear bearings get oil only when you are driving...

So that oil doesn't flood the axle bearings and seals.

Claud.

 

[Claud]

It's not unusual for wheel bearings that have sat idle for a long time to dry out at the top, and fail when a load is put on them.

As has been said, boat trailers are known for this, as are camper trailers and show cars.

Claud.

 

[SatinSilver]

I wonder if it was just corrosion on the rotor and the brake pads are slightly touching the rotor. When the wheel is turned by hand the roughness can be felt. Then when the car is driven the corrosion is removed and everything is ok.

 

[Kamele0N]

Originally Posted By: Claud
Originally Posted By: Kamele0N
Originally Posted By: BrocLuno
OK, so the rear end oil level is often below the bearing when sitting level. They get occasionally oiled when you turn or side hill, park on off camber, etc. Ball and roller bearings do not need a lot of oil. But they need a good residual film.


Thats why I put my finger on filling hole when filling rear diff...to slightly "overfill" rear diff.

I really dont know why all manufacturers drill that filling hole to sit just below the driving axle? So that rear bearings get oil only when you are driving...

So that oil doesn't flood the axle bearings and seals.

Claud.


OK but...the axle doesnt care...bearings are happy when in oil...and seals are there to do their job with sealing...one way or another seals are in better position if oiled then dry....

 

[willbur]

Originally Posted By: SatinSilver
I wonder if it was just corrosion on the rotor and the brake pads are slightly touching the rotor. When the wheel is turned by hand the roughness can be felt. Then when the car is driven the corrosion is removed and everything is ok.


No- I spun the bearing in my hand after it was removed from the hub. Very rough and noisy

 

[clinebarger]

Originally Posted By: willbur
Originally Posted By: SatinSilver
I wonder if it was just corrosion on the rotor and the brake pads are slightly touching the rotor. When the wheel is turned by hand the roughness can be felt. Then when the car is driven the corrosion is removed and everything is ok.


No- I spun the bearing in my hand after it was removed from the hub. Very rough and noisy


Was it noisy in service on the vehicle? Once you remove the Axle Nut clamping force on the the bearing races....The noise/feeling of the bearing is irrelevant.

 

[CR94]

Originally Posted By: Kestas
The only way sitting could cause damage is if the seal failed, allowing static corrosion to occur. But even that is a long shot because water would degrade the grease to where the bearing would suffer lube failure.

In our wheel bearing warranty return, the primary reason for early failure is water ingress from a bad seal. There are other reasons, but we are guessing. Only a proper examination would let us know. Never have we found a bearing that failed in warranty because "it sat too long."
If the bearing was quiet before the vehicle was parked, but noisy immediately after the long hibernation, the only reasonable explanation is corrosion from water that had entered earlier.
In my admittedly limited experience, water ingress is the most frequent cause of wheel bearing failures.

 

[RooflessVW]

Originally Posted By: clinebarger
Was it noisy in service on the vehicle? Once you remove the Axle Nut clamping force on the the bearing races....The noise/feeling of the bearing is irrelevant.

Not on a dual-row ball bearing it isn't.

The bearing maybe had a small defect from new. Maybe there wasn't enough grease in it to begin with. Likely the grease settled in the bearing, and/or moisture got to the bearing.

It happens. Here's a picture of a toasted bearing from Pelican Parts. You can see that there's pitting in one area... Maybe the top of the bearing from a rarely used car?

 

[willbur]

Thanks All for your comments.

I believe lack of grease is a believable explanation for this failure. A YouTube video of a brand new name brand bearing showed very little grease. The techs took the seals off and re-greased the bearing before installation. So sad that such an expensive part (plus R&R cost)lacks an extra penny's worth of grease. Maybe just a one time thing, but who knows? Before anyone blames Chinese, these were made by a German manufacturer.

 

[Kestas]

Are you sure the grease didn't purge from the bearing as a result of the damage? Once raceways spall, the seals can be off track and allow grease to escape. If water gets in, grease can get out. Did you see any grease on the outside of the bearing?

 

[willbur]

Greetings Kestas-
I did not see any grease on the bearing when it was presented to me-perhaps the tech wiped it clean. I just spun it in my hand. It was very rough and noisy.

The lack of grease I'm referring to is what was found in a new replacement bearing; regreased with RedLine SL-2 grease and installed (YouTube video). That grease has organic red moly in it. Isn't moly not recommended for use in bearings?

 

[Silk]

There is very little grease in a prelubed bearing for a reason - you've probably overpacked it.

 

[Kestas]

Rule of thumb is the grease cavity in a sealed bearing should have no more than 30% grease by volume.

Originally Posted By: willbur
Isn't moly not recommended for use in bearings?

I don't think it's harmful for bearings. It's just not an EP (extreme pressure) grease, which wheel bearings need. Moly is more for boundary lubrication.

 

[IndyIan]

Originally Posted By: Kestas
Rule of thumb is the grease cavity in a sealed bearing should have no more than 30% grease by volume.

Originally Posted By: willbur
Isn't moly not recommended for use in bearings?

I don't think it's harmful for bearings. It's just not an EP (extreme pressure) grease, which wheel bearings need. Moly is more for boundary lubrication.

Somewhere I've read that lots of moly allows balls to start skidding instead of rolling which takes the bearing out. I use moly grease in pivots and pins with no bearings, and try not use it in bearings if I can. No wheel bearing grease I've bought has moly in it anyways so I'll stick with that.