Front Wheel Spindle Wear

[JHZR2]

Noticed when I removed the inner wheel bearing on my 82 MB 300CD, that the spindle has some dark spots on the forward half, that feather to bright metal on the rear half. I don't recall seeing this when doing this job on other old Mercedes, granted the last time I did one was long ago.

Is this normal and acceptable?

Bearing had no play, good grease, roll fine, etc.

 

[kstanf150]

Maybe try a little steel wool or very little sand paper to see if it will come off
Could be residue from heat and grease

 

[tom slick]

Can you feel any grooves?

 

[demarpaint]

It looks almost identical to quite a few spindles on vehicles I owned or serviced over the years. I cleaned them up greased the bearings and drove with spindles looking like that for decades. If they're unacceptable that's news to me.

 

[Kestas]

This is called fretting. Fretting occurs when you have micromovement between two steel surfaces. This rubbing sloughs off tiny bits of steel, which immediately turn to rust in the everpresence of oxygen. It is normal to see on the bore surfaces of bearings, as long as it's not excessive.

I don't believe what you have is excessive. Realize the mounting on the spindle is considered a slip-fit, and not a press-fit.

 

[JHZR2]

Thanks. Certainly not excessive; there's nothing even to be felt there.

I'm going with it.

 

[maxdustington]

Originally Posted by Kestas
This is called fretting. Fretting occurs when you have micromovement between two steel surfaces. This rubbing sloughs off tiny bits of steel, which immediately turn to rust in the everpresence of oxygen. It is normal to see on the bore surfaces of bearings, as long as it's not excessive.

I don't believe what you have is excessive. Realize the mounting on the spindle is considered a slip-fit, and not a press-fit.
The literal definition would also be appropriate.

 

[Trav]

Just clean it up a little with a bit of 800 crocus cloth if you want, nothing to worry about there.

 

[berlyn]

I would also propose to find an appropriate anti-fretting grease suitable for the application of wheel bearings of course.

 

[JHZR2]

Originally Posted by berlyn
I would also propose to find an appropriate anti-fretting grease suitable for the application of wheel bearings of course.


I used that green Mercedes-Benz grease in their tube. FSM indicates that in 1982 MB changed grease types, so this car may have had the older type in it at one point. Might also explain why I didn't see this on my 83. Pure speculation...

Just figured it was an interesting thing to observe on some old, high-ish mileage parts.

This was before bearing was set correctly.

 

[berlyn]

Hello JHZR2,

nice to see precision work done on the vehicle.
I am confident that MB chose a correct lube for the application, but are the specs of the grease (thickener, base oil viscosity, extreme pressure characteristics etc) known? Not intending to hijack the thread of course, just asking because of the importance of lube in this case.

See in the following links smearing, could it also resemble the surface of the bearing?


https://www.nskeurope.com/en/services/troubleshooting/damage-by-type/smearing.html


https://koyo.jtekt.co.jp/en/assets/file/pdf/catb2001e_a.pdf#page=82


https://www.ntnglobal.com/en/products/care/damage/index.html

 

[JHZR2]

Originally Posted by berlyn
Hello JHZR2,

nice to see precision work done on the vehicle.
I am confident that MB chose a correct lube for the application, but are the specs of the grease (thickener, base oil viscosity, extreme pressure characteristics etc) known? Not intending to hijack the thread of course, just asking because of the importance of lube in this case.

See in the following links smearing, could it also resemble the surface of the bearing?


https://www.nskeurope.com/en/services/troubleshooting/damage-by-type/smearing.html


https://koyo.jtekt.co.jp/en/assets/file/pdf/catb2001e_a.pdf#page=82


https://www.ntnglobal.com/en/products/care/damage/index.html


The ntnglobal information is good; it's nice to have graphical representations to compare.

Smearing looks to be metallic, while fretting looks like it can be darker in nature. Using that objective standard alone, which might be misapplied, I'd argue it is fretting as Kestas indicated.

Regardless, it looks like adequate preload is a key aspect. As mentioned above, these are slip fit, not press fit (inner ring on spindle). So if that surface doesn't have sufficient protection (very thin ep coating?) or grease starts to go "bad", harden up and affect roller operation, potentially that inner ring will slip under certain circumstances.

You mention precision work. Some folks discuss tightening bearings "tight enough" so that the rotor is tough to turn, then back off 1/3 turn (or some variation of that theme). Given that preload is a theme in both fretting and smearing, it's likely that someone didn't tighten the bearings properly and not have enough preload. Movement is per the fsm 0.01-0.02mm. Having done this job twice in the last week, it's clear to me that the difference between tight-ish and way excessive play is maybe 1/4-1/8 of the turn of the outer nut. Even torquing down the tightening Allen bolt can affect the preload enough to have to go back and turn it a few radians and check again.

The grease used until sometime in 1982 was sheet 265.0 grease. Beyond then, 265.1 high temperature antifriction grease was employed. No idea what is in my bearings.

I used MB grease, which is listed here:

https://bevo.mercedes-benz.com/bevolisten/265.1_en.html

I suspect that the Mercedes labeled grease tubes are actually FUCHS RENOLIT LX-PEP 2 GREEN GREASE. This is a lithium complex grease with mineral oil.

https://cdn.shopify.com/s/files/1/0733/4657/files/RENOLIT_LX-PEP_2.pdf?3815706689861459605

There may be other greases from Schaefer or Mobil 1 or otherwise which offer better operating or frictional characteristics, but the green color imo is pleasing and might be useful to see how the grease changes or gets dirty in time.

FYSA bearing photos are attached.

 

[berlyn]

Hi JHZR2,

would a product like one of the below be appropriate in a similar situation (of a low strength if possible) in order to avoid rechecking the preload by the tightening of the allen bolt (after curing)?

https://www.henkel-adhesives.com/us...tedSearch.category=Retaining%20Compounds

Usually the ring relative to whom the load is rotating, is the ring to have a slip fit and then preload, or an interference fit.

 

[Kestas]

The best grease for wheel bearings is Mobil Infinitec 152. It beats out Mobil 1 for wheel bearing performance. Unfortunately, it isn't sold in small quantities for the consumer. A quick search reveals you can buy a drum for $1900. Luckily I have a small pail of it at home, which will meet my needs for quite a while.