Q. I think I may have gone too long without maintaining my metal-sealed ball bearings, because after I sprayed them out, one still feels rough. No matter how much cleaner I spray, it still doesn’t get better. Should I replace the bearing?
A. Chances are that your rough bearing is still salvageable. You encountered a very fine piece of debris that has worked its way into the metal seal of the bearing, and now it is lodged inside the bearing. Since spraying alone didn’t remove the debris, you need to remove the metal shields and spray the internals directly. To remove the shields, grab a micro-sized flathead screwdriver and throw on a pair of safety goggles to be cautious of a flying c-clip mishap. Use the corner of the screwdriver and pry it under the back of the c-clip near its opening, and remove it from the bearing. This will allow you to remove the metal shield by tapping the bearing upside down, exposing the bearing internals. Now, use cleaner to blast it out; spin it a few times with your fingers, and repeat until the grit is gone. Once it runs smoothly, place the shield back in place, carefully pinch the c-clip closed with your fingers, and drop it back into the bearing housing. Finally, place a drop of synthetic oil in each side of the bearing, and you’re done. To prevent this from happening in the future, spay your bearings frequently, using RC-specific bearing/motor cleaner and RC bearing oil. If you really want to make quick work of cleaning your bearings, pick up an RPM bearing blaster.
If spraying out your metal-sealed bearings doesn’t remove all the grit, you can disassemble them carefully with a small flathead driver, remove the metal shield and spray out the internals for a more complete cleaning job.