Bearing pullers are specialized mechanical tools that pull the bearings off of axle shafts. Although there are many different types and designs, they all work on the same principle. A set of jaws will hook onto the outer sides of a bearing lining or bearing case. Bearing pullers with jaws that hook onto the inside of a bearing lining are called a "blind-hole bearing puller." A central bolt or a slide hammer is then used to put reverse pressure onto the jaws that grip the bearing lining until it comes off and away from the axle.