Cleaning Bearings

The procedure to clean bearings is as follows. You need a little bit of benzine (without oil). I heard that terpentine works too. Pour a centimeter of benzine in a cup. Hold the inner ring of the bearing (I use a peg or cotton bud), and hold the bearing in the benzine while rotating the bearing with a cotton bud.
A lot of small metal particles probably comes out. Continue rotating the bearing until it is clean (a few minutes or so). Take the bearing out and let it dry a few minutes. Don't wait long before regreasing, to avoid corrosion of the steel.
Now, if the bearing is OK it should make a sizzling sound when rotated. Also without grease it should rotate freely for some 6 to 10 seconds when given a good starting rotation. But if it feels sandy and there are sharp edges when rotated slowly with the finger as if there is a hair inside, or when it rotates only 2 to 3 seconds when kicked into rotation, you need a new bearing. Sometimes the bearing blocks at some point, while it rotated fine when there was still grease in the bearing! In this case you may continue cleaning, maybe some more dirt was still inside. If the bearing sounds right, you can reuse it.

Cleaning the bearing with benzine.

I used to grease the bearings with silicone oil, but the problem with that is that the oil is slung out with fast rotating bearings. Now I use the "The Greaser" to put in Union 76 grease for all bearings after cleaning, and also put this in new bearings. For more information on Union 76 and the greaser go to PetersRC. You can also use chain oil (for bicycles): you can heat this oil so that it gets thin, once in the bearing it gets thick again. Thanks to Rob from Quartel for this greasing-tip.
If you have to press-fit the bearing into aluminium, you may have to heat up the aluminium first. Union 76 will start boiling (going out of the bearing and turning white) when heated to 225 °C so heat your aluminium at max to 200°C.

© W.Pasman, 22/4/3