With the pins removed, shake the caliper and the pads will fall out. Check them for cracks, missing pad material and general wear (5). There are telltale lines across the face of the pad; when the pad is worn to the bottom of these grooves, they're done. Before you toss the pads, use some aerosol brake cleaner to remove grime and pad residue from around the caliper pistons (6). Then reinsert the old pads and wedge a chunk of wood (or a large screwdriver) in between them to push the pistons back into their bores (7). As you do this, look at the master-cylinder reservoir to make sure fluid isn't overflowing.