Lawrence08648

I just read an article about greasing sealed bearings. You carefully pop off the black plastic seal, put grease on top of the bearings and then put the seal back again. Has anyone tried this? When you did it, were the bearings dry? How easy does the plastic seal come out? How easy is it to damage the plastic seal? How do you damage it, rip it? Bend it? What happens if you damage it, what do you use to replace it?

davidad

I have cleaned and regreased sealed radial bearings. You need to be careful when popping the seals out. The seala metal backing that can be bent, but you can straighten it if necessary.
I like these bearings because the retaining ring is easy o remove and replace. https://www.enduroforkseals.com/id138.html

MileHighMark

It's definitely not difficult, but you need to be careful removing the seal(s). Use an x-acto knife and pry from the outside of the seal (to avoid damage). I've done this several times, and it's always been worth the effort.

Charles Ramsey

The way ALCOA does it they put the bearing in a can of grease then they put the can of grease in a vacuum chamber and suck out all the air. When the vacuum chamber is repreassurized the grease is sucked into the bearing.

dvs cycles

Sounds like a good use for my food saver bags.

reptilezs

a utility knife easily pops out the seals. the cartridge can be disassembled or flushed with solvent. to disassemble push out the retainer and drop the balls to the bottom, then separate the races

Lawrence08648

I thought about it. I won't push the grease into the bearings. It will suck out the air while leaving the grease and the bearing there, separated. It won't work.

3alarmer 

Hence the terminology ?

jgedwa

Well, they are not really sealed. Its really not practical for the seal on a bearing to be truly air-tight. It does have to turn, afterall. Sealed bearings just have more of a barrier than otherwise. Keeps out the big chunks of air and such.

jim

Charles Ramsey

It does work ALCOA had some severe service bearings where the grease would boil out leaving them full of air. My father was working on a way to pump molten aluminum using magnetohydrodynamics. It seems molten aluminum is hard on regular pumps go figure. Of course this method does not remove any dirt or old grease in the bearings.

canopus 

Yes, did it alot especially after the lake jumping runs as a kid. As others have said, you just have to be careful removing the seals (If I used an exacto knife it would be a DULL one) I prefer the small pin/curved hook tools from Snap-On (or Harbor Freight if on a budget).

Burton

In fact its pretty straightforward with most sealed bearings.

What I`ve never been able to do is evaluate the condition of the bearing races to confirm that the bearing was indeed still in perfect shape. The ball bearings are harder than the race so their condition isn`t a good indication and the bearing cages block any inspection of the races themselves.

So regreasing and reinstalling sealed bearings is pretty much a crap-shoot. Just because it spins freely after cleaning is no guarantee its in good shape. Bearings only perform as designed (or not) under load.

mrrabbit 

It's easy...do it when the bearing have sat for several years and the problem has become caked grease as opposed to worn units. Spin afterward for about 5-10 minutes and voila - they feel like new. Does nothing for bad units though. Everything has to be replaced at some point.

=8-)

Razor blade type knife seems to be a good tool.