Reel ball bearing shields and seals are designed to keep lubricants in the bearing and contaminants from entering the bearing. Some bearing shields are not removable, which can make cleaning and re-lubrication more difficult, and other bearings use a shield design that only covers part of the opening.

Ball bearings may also be equipped with removable shields or seals that allow for easier cleaning and lubrication. This type of bearing is frequently used where grease is used to lubricate the bearing, since grease is more difficult to remove and replenish than oil lubricants. All removable shield reel bearings have a spring metal retainer that fits into a groove on the outer race, so the shield is firmly attached to the outside race, and it never really contacts the inner race.

The easiest way to remove a small radial bearing shield is with a sewing machine needle and magnifying lens. You can carefully prying the tip of the needle into the groove near one the end of the retainer, to work the retainer out. (Be careful to cover the other end of the retainer to keep it from flying out and becoming lost, since it is under spring pressure.)  Once the retainer is out, the shield can be removed, and bearings and cage will be exposed.  Just reverse this process to reinstall the shield