Role of the copper insert tab in the front axle next to the hub locknut?
 

I'm doing a rotor and front wheel bearing replacement in my 300sdl and came across these little copper insert tabs that connect in the center of the axle with a flap that appears to be in contact with the allen head locknut.

What is this copper tab for? Something to do with the ABS? How should I replace these, new ones come with my wheel bearing kit.

Thanks for any help or suggestions

I believe this is a grounding contact for the brake wear sensors if my memory is correct...if you remove it the wear sensors may not function. I'm sure others will correct me if I'm wrong.

I thought is was something to do with radio interference. But whether they are there or not has never seemed to make any difference as far as I can tell.

Grounding path for electrical noise which can be generated by rolling tires.

I've been told it is there to dissipate the static electricity caused my the Iron in the brake pads. If this static electricity doesn't have the tab providing ground, the electricity will flow across the wheel bearings. long term this can cause the bearing material to electroplate itself to the races accelerating bearing wear.

good stuff
 

i always just thought vaguely something about static electricity and always tried not to damage it.

this is good though.

tom w

Just rebuilt the 300D frontend
 

- Manual says it's a contact spring or radio static supressor...

bnc