Wheel Bearings

[Hillclimb#42]

Recently made a discovery. I just had to replace the wheel bearings in the 250. I was kinda whining about just buying them and the guy at the local bike shop told me a good one. He said that he always pops bearings open and fills them with grease. They last ten times longer that way. I was like, "thats a sealed bearing" he said that its just a rubber seal and to pop them out with a pick-like tool.

There they were. New Bearings, No grease. The seals pop off easy and both inside and outside can come off just as easy as the other. Neither side of my All Balls bearings were greased. Can anyone tell me why they would be absent of grease? Thought I would pass it on.

[BDI]

I thought all sealed bearing came pregreased. I know they don't have a ton of grease because there is no benifit to over greasing bearings. To much grease can cause other probs in my opinion.

[kaw rider]

kyle   those bearings need to be service very often. we have removable covers to make the job easyer.

[Hillclimb#42]

Mine may have had a greasy film on them, but I could not say they were greased from the factory. None was apparent to the naked eye. I had always greased the lips of the seals, the axles, and even the collar/spacer deal in the middle. I have never tried to grease a sealed bearing. I'm still learning...

[maddoggy]

a bearing that is lubed by grease must not be filled past 1/2 way with the proper grease. overfilling with grease results in churning which develops excess heat. heat + bearings = spalling or other bearing race damage. trust me, i have been trained by timken bearing company.

[Goat]

a bearing that is lubed by grease must not be filled past 1/2 way with the proper grease. overfilling with grease results in churning which develops excess heat. heat + bearings = spalling or other bearing race damage. trust me, i have been trained by timken bearing company.

That's great advise. I did not know that. Thanks

[Friar-Tuck]

 The sealed bearings are just like the kids sealed bearings on their skateboards, The only way I found out about that was after the boys ruining good bearings. I got Better ones and they came with instructions for cleaning and care.
    I just never thought to post anything like that, Thanks #42,!
 
 I didn't know about any more than 1/2 the bearing with the grease, Thanks Dawgy.
I did find out what happens when you do "Pack" them... the grease heated up and blew past the seals...
  Maybe I can find a post on removing and replacing the bearing seals.  You do have to work slowly, I have Ham fisted the first few apart and bent the thin steel "washer" the rubber was vulcanized to..
  I'll look for a post...
  Here's a pretty good write up for a bicycle bearing, pretty much what I've found the same for the bearings I've done.
http://maintainthatride.blogspot.com/2008/06/con-tent-thyself-get-it-its-supposed-to.html

And for what it's worth:
http://findarticles.com/p/articles/mi_qa5322/is_200412/ai_n21360835/
  Tuck\o/   

[maddoggy]

actually, timken school taught me to fill the "free space" in a greased bearing cavity 1/3 to 2/3 full, but as a general rule i try to go with a happy medium. thus i recommend 1/2 way filled. the "free space" i'm refering to should be considered with any greased bearing application whether it be a wheel bearing cavity on your truck hub or a sealed individual bearing or whatever else you may work on. alot of mechanics pack their wheel bearings but fail to consider that the grease will not stay in the bearing when it heats up to normal operating temps. unless the entire cavity(free space) is filled to the proper level. i don't mean to sound like a know it all, i just know this info and figured i would share it.

[KXcam22]

Also keep in mind that grease is just a clay or soap type medium (lithium, sodium, calcium etc) that is used to hold a lubricating oil in suspension (essentially so it doesn't run out). The medium has a microsopic pourous structure like a sponge. I have popped off the seal on old bearings to add some grease but I have not regreased a new one. May have to try that. Cam.

[KXcam22]

When I got my new motorcycle trailer I regreased both wheels. One had no grease and one had water instead of grease. Hmm. Cam.

[BDI]

I pop the seals with a pick then clean the bearing with solvent,warm soapy water, dry with compressed air being careful not to over speed the bearing, pack the bearing clear full rotate the bearing several times to make sure the balls and races are coated good.Then I wipe off every bit of the exces grease with in reason and pop the seals back on. This way you have grease where you want & need it the most,the balls & races.

[dirtjunkie85]

sweet! I had never heard of that. great info to know.