Thoughts on this bearing

[mbaker]

I pulled apart these hubs for maintenance and this is what I found. Tandem axle boat trailer, new bearings 6 years ago, Lucas marine grease, brakes on all hubs. Probably only have 2000 highway miles total as it didn’t get used much those years. In and out of water maybe 3 times each year.

All 4 hubs were similar grease around the bearings was dark and discolored but still thick and greasy, did not feel broken down. Any grease in the middle of the hub or cap away from bearings still had original Blue color. Nothing seemed necessarily alarming and all bearings looked good and shiny except this one. Had a colored streak on the rollers but the race was fine. The 2 bearings side by side for comparison. I’m putting all new bearings in any way but I wouldn’t be scared to repack and run the rest of then, even this one is smooth just discolored. I temp check on long runs and never see more than about 140 on a 95 degree day and using brakes to stop, and they have never been out of adjustment.

Is this a grease issue, contaminant issue, or material issue?

 

[spasm3]

Look fine to me, possible the bearing discoloration was from a heat. Maybe the bearing got hot on its first run after being installed, if the castle nut was a touch too tight.

 

[tnt_motorsports]

I think it's a preload issue. That bearing looked to be too tight IMO. How did it turn before you took it apart?

 

[mbaker]

It was smooth rolling just like the others. I don’t think preload is the issue, there was just a very small tick of play since they were installed and also I would think the inside bearing would be similar. Unless that cap let in a little water and contaminated that bearing more it seem strange that only this bearing and only the rollers are discolored. The race looks like new, no color and no marks at all. The grease in the inside bearing looked just like the grease in the outside bearing.

 

[mbaker]

I took another look, it looks better in person yet still stained but not as noticeable until you put it side by side. I took a look through magnifier and it’s all smooth no pitting or grooves. Honestly If I was in a pinch I’d run it but as cheap as these are I’ll just replace it. I’m wondering if this might have something to do with the bearing material or if this one bearing just stained easier?

 

[Exhaustgases]

Getting hot not good for the heat treat.

 

[Variant_S]

The Timken Bearing Damage Analysis Reference Guide suggests on page 10 that this could be a mild case of inadequate lubrication.

 

[MasterSolenoid]

If you're going to replace any bearings, I suggest getting: Made in USA.
Some inexpensive bearings made in China could have a problem right from the start.
You can't tell just by looking. .... (poor steel, poor heat-treating).

Buy made in USA
Don't over-pack with grease
Do preventive maintenance
You'll be good to go.

 

[Kestas]

I agree the color indicates a heat related issue.

 

[mbaker]

I went to the trailer store today to grab new bearings and had them take a look at this one. They thought it looked like it was just a little wear and discolored appearance from the wear pattern.

 

[Rust_Belt_Pete]

If you're going to replace any bearings, I suggest getting: Made in USA.
Some inexpensive bearings made in China could have a problem right from the start.
You can't tell just by looking. .... (poor steel, poor heat-treating).

Buy made in USA
Don't over-pack with grease
Do preventive maintenance
You'll be good to go.

Too many common application bearings out there dont have USA made sources. A whole bunch of ford SUV's only have bearings made in China.