This is what a "noisy" wheel bearing looks like when you tear it down.
There's a lot of ways to end up here, but a lot of times, it's something we did.
... to put it another way, they don;t fail in service very often without a cause.
When they start to make noise, you're hearing the effect of unround balls rolling in an unsmooth race
This happens a couple of different ways, but it usually starts with a flat spot on one or more of the balls and/or a "dent" in the race.
The most common way this happens is flat rate mooks have used an impact gun to install/remove the axle nut while performing one service or another that requires the removal of the front axles. It's torque spec is (grrrr, can;t remember off the top of my head
... so I'll just say, preetty fawkin tight
and the "rattle" of the impact gun will pound the assemble in a way they will never see in service, especially when a gun is used to tighten them!
Nothing drastic happens,
... immediately ...
and a few folks will probablly argue that they do it all the time with no problems.
Thing is, they have just for all intents and purposes, perfomed a brinnell test between two very
hard surfaces, and either the ball now has a flat spot, or the race has a small dent. gaur~an~damn~teed
Now, every time the flat spot of the ball hits the race, a high shock loading will be delivered to a very small local area. This will make a teeny, tiny dent. Over time, enough denting will occur to make the surface of the race bumpy, which fawks up the rest of the balls, which procceeds to make more dents,
...eventually the thing looks like ten miles off washboarded road, and none of the balls are round.
(Click on the pic above, then click the "+" over the race on the left, that's ~1000 miles after an axle replacemet where McGilla the Gorilla used a gun to tighten the axle nut)
... sounded like there was a dc-3 taxiying for take off up in the front of the car.
Another way to end up here is by applying a load without an axle in place, holding things together.
A lot of times, folks will pull the axles to yoke the motor/trans, and then life intervines and the car has to be moved.
... without an axle in it/the outter c.v. pinching the two races/halves together, the races can 'walk" on the hub.
Again, nothing drastic happens
And a lot of times, you might get lucky and get away with it, but many times things don;t cinch up just like they were. When you install an axle and tighten things up, the preload will be off when you do torque it up.
... too loose, and then the balls won't track well, and they'll make an oblong "orbit" instead of just rotating symmetrically in their races.
Again, you might get a couple of thousand miles out of it before it starts making noise,
... but the faster you drive/more you load it up in the twisties, the sooner it will die.gaur~an~damn~teed
To keep things pinched together, I've used a couple of t-case bolts combined with a couple of nuts and large area washers off the front crossmember as a get by/temporary solution.
... anything to keep it all squarshed together so the car can be moved.
Unfortunately, even if you think ahead and cobble something together, it won;t seal up very well, and this can allow dirt and moisture to enter.
...that's what killed the bearing on the right in the top picture. Buddy listened well and cobblefied some random hardware and pinched it together. he then rolled it over to the wash bay and procceeded to steam the engine compartment till it was clean
... got about 500 miles down the road, and things went sour.
This is why this is my favorite technique for dealing with jsb status is to "ginzu
" an old axle and use the stub as a prop. This lets you torque things back up before applying any load, so nothing moves.
It seals up well enough to steam the engine compartment without contaminating the bearing, and you can roll it over to the wash bay without hurting a damn thing.
... hell you can even load it on a roll back and move it from shop to shop
... for years
... like a lucky charm
... not that I would know anything