Just to clarify: On some earlier FWD vehicles, a loose axle nut can lead to separation of the inner and outer bearing races and loss of as-manufactured bearing preload. However, the new generation of these bearing assemblies, such as used on HHR, are independent of this requirement, and will not separate, even without the axle nut.

 

But only in an unloaded condition. Put weight on that unloaded bearing and the bearing races will separate (at least partially). At this point the tolerances responsible for the correct preload no longer exist.

My argument here is that while preload may not be "adjusted" as in years passed, it is still "maintained" or "preserved" by the axle/axle nut/torque combination.

They also cannot be serviced in the shop, only replaced!

 

Almost true...at least as applied to older vehicles than HHR. However, your point was about assembled axle nut torque affecting or being critical to assembled bearing preload, as in more torque can produce more preload and therefore possibly damage the bearing. This is Not true.

The fact is...the new generation bearings (as on HHR) also no longer require the axle shaft to keep them together. They work as well either with or without the shaft. It's a new method of manufacturing that you may not be aware of yet.

A practical demonstration of this is in the front spindles of the RWD Solstice and Sky. They have no axle shafts, but are the same bearing/hub assembly as used in the Cobalt and HHR.

 

As noted in my last post, this is an incorrect statement....at least where HHR is concerned.

 

I would like to see an exploded diagram on this "new" design. My experienced with "new" is that's it's usually a rehash of something old. I would still maintain that the axle nut torque would have some affect on maintaining the designed preload. I'm designing the experiment already! :)

 

EcoBoost, can you point me to more details on this? I'll check out the Solstice and Sky.

 

It's a unique setup for sure. Whereas one could press apart the previous generation FWD bearings that required the axle shaft to stop the bearings from separating, the new generation bearings are not able to be disassembled. I won't claim engineer-level knowledge of this new bearing assembly technique, but to me it appears that once assembled, the inner hub is then swaged outward to capture the opposite side bearing.

 

When you see the new design, it will finally make sense to you

And no, it does not require the axle nut to stop the bearings from separating.

 

I was simply stating what most techs and obviously the OP do. I didn't advise him to do this.

OK.

Does the word trolling have any meaning to you on this part of your post? I hope that's not the action you were trying to accomplish.