If you drawer slides are not sliding smoothly and are worn out, replace them yourself and save money. Drawer slides allow the drawer box to be pulled from the cabinet. Undermount drawer slides are not visible when the drawer box is pulled open. The drawer slide is mounted under the drawer box. This allows you to use a larger drawer box. Most undermount drawer slides have a soft-close mechanism built into the drawer slide.
Measure the depth of the drawer box to determine the length of drawer slide needed. You'll need a drawer slide equal in length to the depth of the drawer box.
Remove the drawer from the cabinet. Mark a 1 3/4-inch-wide notch on each side of the drawer box back. Mark a line to the drawer box bottom with a pencil. The depth of the cut will vary depending on how your drawer box is constructed.
Cut the notch from the back of the drawer box to the drawer box bottom, using a hand saw.
Measure 7/16 inch up from the notch with a tape measure. Mark a line, using a pencil.
Drill a 1/4-inch hole into the back of the drawer box, using a power drill. The hole should only be 3/8 inch deep. Avoid drilling completely through the drawer box.
Install the left and right disconnecting levers to the drawer box bottom. Attach the two levers with 5/8-inch screws and a power drill.
Position the drawer slide into the cabinet opening. The drawer slide should be mounted flush with the bottom or the stretcher of the cabinet. Align the undermount drawer slide with the face of the cabinet.
Screw the drawer slide into position, using 5/8-inch screws and a drill. Use at least four screws to fasten the undermount drawer slide.
Repeat this process with the opposite side of the cabinet box.
Slide the drawer into the cabinet box. Check that the drawer slide engages with the release levers on the drawer box.
Do not force the drawer box into the cabinet opening.