Bearing Maintenance - Spindle Fretting

[TG10894]

I have a 2015 Cougar 21RBS TT that I have owned for ~1yr. I have started pulling the wheels for bearing/brake inspections and came across discoloration of the inside bore of the bearings and "only" on the bottom of the spindle for both inner and outer bearings. Other than the color, the surfaces are otherwise smooth. The rest of the bearings and races look good, and it was well lubricated. (pics below)

Question - After researching here and other forums, it may be fairly common and is called bearing fretting. Have others seen this, and if so, what did they do to address short-term and long-term?

After cleaning up the spindles, I plan to replace the bearings, races, and seals on all four tires with either National or Timken to "re-baseline". As a side note, it was easy to find the bearings locally, but not so easy to find the "double lip seal" needed for EzLube axles. The single lip seals and not nearly as robust, and and not spring loaded like the double lip seals and may cause some of the "blow by" into the brake drum some people have commented on that have used the EzLube feature.

[mfifield01]

I had the same thing on mine. I was told it was grease staining. I did mine in February. I light sanded the area, but not much at all.

I put new Timken (USA) bearings/races on mine.

[slow]

I am no bearing/shaft failure analysis expert, but you may not have had sufficient preload thereby causing the shaft and inner race markings you are witnessing.

Hopefully other more knowledgeable than me will comment.

[AbHDToyHauler]

Fretting can also be corrosion. If the bearing gets moisture between bearing (mounting ) surfaces then fretting/corrosion can occur. Also if for example its easier for the bearing to rotate at it's mounted area rather then it's rolling surfaces then fretting can occur because the two surface are rubbing against each other which they weren't designed to do. Either one can be a common problem for example when moisture invades or a bearing is close to seizing and it's easier to rotate complete bearing.

[travelin texans]

Originally Posted by AbHDToyHauler

Fretting can also be corrosion. If the bearing gets moisture between bearing (mounting ) surfaces then fretting/corrosion can occur. Also if for example its easier for the bearing to rotate at it's mounted area rather then it's rolling surfaces then fretting can occur because the two surface are rubbing against each other which they weren't designed to do. Either one can be a common problem for example when moisture invades or a bearing is close to seizing and it's easier to rotate complete bearing.

Yea! What he said!
Could've also been the original high quality Chinese factory bearings. Clean it up with some steel wool or super fine Emory cloth & put it back together.

[flybouy]

You want to polish the area with somefine emory. It shouldn't hurt the spindel.