How to ruin a magnetic ABS speed sensor

Keep it away from magnets...there are magnets buried in the bearing seal for the speed sensor to read as the bearing rotates. If these internal magnets get damaged, the ABS might not read correctly. Magnetic viewing film was used to show the magnetic field from the tone wheel. It should be uniform all around the bearing like spokes on a wheel.

Video shows what happens when rubbing two external magnets on the magnetic gone wheel of the bearing. One magnetic didn't seem to hurt it, the other completely erased the signature. This is from a 2006 Toyota 4runner front.
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