Pitting in Bearings

[Jan_P]

Pitting in Bearings
I have recently Done spring service on Bicycles. Lubing chains and some minor stuff. For ladies
Checking the gear shifting and some paint. Keeping the rust away

While at it I started to rebuild rear hubs and Wheels -- Getting bypassed by the youngster so it says Swish .Trying more gears.

Sachs Torpedo 3 gear internal Planet gear

The issue -- one hub has a worn bearing # 16 and on the race there is a very very very very minor pitting on one spot # 17
The bearing I can buy .but the race can be more difficult .. The same problem happens on Motorcycle bearings also.
Up til now I have always replaced .But it might not always be possible if it is very old machines no parts.Available

Have anyone any experience on this .Is it a no starter putting in new balls in a slightly pitted race. even though very very very very minor pitting
it is there.
Anyone done that ??

 

[40north]

I have cleaned and greased many pitted ball and roller bearings. I use a high content moly grease (chevron). They work for a long time. What caused the pits? Foreign materials, water/corrosion? Overloads? If cause is gone, probably last long time with moly.

 

[Jan_P]

Thank you Sir

 

[joebgd]

That is interesting. Is moly grease comparable with Lucas tacky red grease?

 

[40north]

Compatible? I don't know. My experience has been, though, that if you examine the containers that greases and oils and stuff comes in, there's a telephone number and maybe a website. Several times I have availed myself of the expert advice from a very happy to chat industrial chemist. You'll have to contact each product chemist cat individually. Understand, these guys are bored and happy to be asked thoughtful questions. Plan on taking notes, and have your numbers ready, like CAS Numbers or SAE specifications, you know. I avoided ruining a big diesel by contacting the chemists.

The conservative approach is to go with one clean bearing and pack it with fresh grease. That would be my preferred choice. People tend to over-pack some bearings, and that can be a problem, depending.

I have used moly in gearcases that were failing, adding it to the EP grease, 90# or whatever. The old VW transmissions took a full tube, and lived another 100 grand. I know!

Oh! Yes, it's probably important to discover why there are pits, and maybe even examine the surfaces with bright light and a microscope. On line you can find illustrations of typical bearing failure modalities. One reason is stray electrical currents, another is contamination, yet another overload, and so on. M/C neck bearing sometimes carry current, and they ought not to, for example.

Hope that helps. Best!

 

[joebgd]

I think I would have just used red and tacky but the more I learn maybe Molly grease is better for wheel bearings? Idk I'm about to get sealed koyo shell bearings all around. I believe I don't have to pack them. Should I apply a little grease on outside of em?

 

[Jan_P]

I think I would have just used red and tacky but the more I learn maybe Molly grease is better for wheel bearings? Idk I'm about to get sealed koyo shell bearings all around. I believe I don't have to pack them. Should I apply a little grease on outside of em?

I dont know exactly where you are installing .But generally speaking one rarely makes a mistake having some lubrication.
Assembling.
I dont believe I have ever seen someone not doing it .
Molybdenum disulfide grease was used on the Excavators .. Crane bearings Sliding bearings

 

[joebgd]

After a bunch of research, I'm going to use good quality lithium grease. I don't need Molly infused.