Drawers absorb a lot of punishment, are often abused and frequently overloaded. The hardware is somewhat flimsy, with small wheels, rollers and bearings that wear out and require replacement. Manufacturers supply replacement slides for just about every application.
Under-mount drawer slides, one of the most common, mount to the bottom of the drawer, and the tracks mount to the cabinet. Bottom-mount have two configurations; one is bent at 90-degrees -- it's the most common -- and fits over the edge of the drawer. The other type of bottom-mount is flat, and even though it attaches to the side at the bottom, is considered a bottom-mount, primarily because the matching track attaches to the bottom of the drawer.
An economy version of the bottom-mount has only one mount, centered on the drawer or cabinet. It may or may not have a corresponding track, but instead, a simple wheel that fits into the track. This type is usually installed on production or affordable cabinets and desks with lightweight drawers.
Side-mount slides telescope to pull the drawer out farther than bottom- mount, and attach to the sides of the drawer and cabinet. They are typically capable of handling more weight than bottom-mount. Side-mount slides typically attach centered on the drawer, but other styles, such as the European side-mount, attach on the side of the drawer at the bottom, but shouldn't be confused with a bottom-mount, which does not telescope.
Check This First
If you're having problems with drawers, it might be a simple fix. The key to smooth-pulling drawers is oval-shaped holes for the adjusting screws, and most slides have them. Fit the wheel on bottom-mount, or fit the drawer slides to the cabinet slides on center mount, and slide the drawer into the cabinet. Move it forward and back a few times. If it rubs or sticks, or is too tight, loosen the screws in the oval-shaped holes, and tap the drawer or track up, down, or to the left or right as needed and test it again. When the drawer glides smoothly, tighten the screws.
They don't work as smoothly, but wooden slides might be considered the most reliable over the years. Wooden slides typically consist of one T-shaped glide, with a corresponding channeled track. The two fit together to facilitate movement. They wear out when wood cracks or splinters, or fasteners pull loose.
Wooden slides that have cracked or split can sometimes be repaired with glue and clamps. If screws or nails have pulled loose, drill new holes and reattach them. If they're too damaged, make new wooden slides. Use the old slides for reference, and cut new ones with a table saw and dado blade.
The cheapest version of a track is nothing more than two plastic pieces that slide against each other. If they pull loose, simply remove and replace them.
Types of Wheels
Most bottom-mount guides rely on nylon wheels, which wear out. The wheels are typically attached to the drawer slides, fitting into channels on on the cabinet slide. It's easy to spot a nylon roller: it's typically extended at an angle, at the back end of the slide on the drawer.
Side-mount slides, because they usually employ ball-bearing rollers, are more efficient than nylon wheels. The ball bearings are typically inside both of the corresponding slides.
Wheels and bearings can't be repaired, and replacement parts for them are typically not available. Slides are replaced and repaired as a unit, and they don't come separately. When purchasing, you'll get four coordinated slides in a kit.
Do Your Research
Before you attempt to replace the slides, remove one of the drawers and decide what type and size you need. If the length is not stamped on the slide, measure it and select the size that fits.
Slides are always labeled for installation. Once you're removed all four parts -- two pair -- from the kit, examine them for stamps. The slide marked DL installs to the left side of the drawer. The slide marked DR screws to the right side of the drawer. The slide marked CL screws to the left side of the cabinet opening. The slide marked CR screws to the right side of the cabinet opening.
Disconnecting Slides From Cabinets
Most under-mount slides pull out and release the drawer from the cabinet; you may have to jiggle the drawer to get it to release. Most side-mount slides employ a lever or tab to release the drawer, located halfway on the slide when the drawer is in the open position.
How to Replace Slides and Tracks
Remove the drawer from the cabinet. Use a drill/driver to remove all of the screws from each one, and examine it for length and type. Obtain a kit of four new slides that match them.
Remove the four pieces from the packaging. Separate two slides marked DL and DR, and screw them to their respective locations on the drawer with a drill/driver and the screws provided in the packaging. There are two, oval-shaped holes at each end. Place screws in them, but tighten them only lightly, as they are adjustment screws.
Separate the two remaining slides. Screw the slide marked CL to the left side of the cabinet on the inside. Screw the slide marked CR to the right side.
Slide the drawer in and out of the cabinet. If it doesn't slide smoothly, loosen the screws in the oval-shaped holes, tap the drawer in the direction needed, test again and repeat if needed. Tighten the screws when the drawer glides smoothly.