Drawer runners, also referred to as drawer slides, allow drawers to slide easily in and out of their housing. Drawer runners consist of two pieces that are "mated," meaning they fit together to work, and if either "mate" is broken, the other does not properly function. Often, you can repair your runners at no cost, but sometimes, the only repair for a broken runner is to install a new set of runners.
Pull out the drawer as far as it goes, then lift the drawer by its sides. This pulls the drawer off of its runners.
Put the drawer directly back into its housing. Sometimes the two sides of the runners only need to be realigned. If reinsertion doesn't work, remove the drawer again.
Examine the drawer runners attached to the drawer as well as those attached to the interior slot from which you removed the drawer. Use a small flashlight if the slot is very dark. Look for obvious defects such as bent runners or too-loose screws.
Reshape bent runners by grasping the metal with the pliers and bending the runners back to their original positions. Re-insert the drawer into its slot. If the drawer still doesn't properly slide, take the drawer back out and try again. If the drawer won't smoothly glide after multiple attempts to reshape the runners, remove the runner.
Tighten loose screws. If the screw holes are stripped, remove the screws from the stripped holes and install those screws through other screw holes; most drawer sides have many screw holes along their lengths.
Remove runners by unscrewing them from the drawer as well as the interior of the drawer's housing. Take the old runners to a home improvement store to find a match or a comparable set of runners. Install them following the packing instructions.