How to Remove and Replace Screwed Undermount Drawer Runners Safely

December 3, 2025

Proper dismantling of a screwed undermount drawer runner requires manually releasing the drawer box via the front locking clips and subsequently unfastening the fixing screws from the cabinet carcass.

Replacing defective or outdated runner systems in kitchen base units or living room furniture is a standard repair task. When a drawer judders, no longer closes completely, or loses its load capacity due to wear, the carcass runner must be removed. Concealed systems are typically traditional undermount drawer runners that sit invisibly beneath the drawer base.

This guide is aimed at fitters and experienced DIYers. It explains in detail how to safely remove screwed runners from the cabinet carcass without damaging the base material, and what to consider when selecting replacement components regarding nominal length, mounting type, and hole patterns.

Difficulty Level and Time Required

Difficulty: Medium (basic knowledge of furniture assembly and working with the System 32 hole pattern required).
Time required: Approximately 15 to 20 minutes per drawer.
Objective: Non-destructive removal of old runners and preparation of the carcass for replacement fittings.

Required Tools and Materials

The following tools are strictly required for dismantling and installing the replacement runner:

Cordless screwdriver or manual screwdriver with a PZ2 (Pozidriv) bit for standard chipboard screws.
Screwdriver with a PH2 (Phillips) bit or matching Torx bit if alternative fixings were fitted.
Vernier calliper or precise folding rule to determine the nominal length in mm.
Bradawl or centre punch to mark new drilling points.
Optional: Wood glue and wooden dowels (Ø 5 mm) if old screw holes in the chipboard are stripped and need repairing.

Step-by-Step Guide: Removing Drawer Runners

The interaction between the runner and drawer works like a railway coupling – only when the mechanical latch is completely disengaged can the drawer box be lifted safely from the track. Using force here will inevitably break the plastic components.

1. Release and remove the drawer box

Pull the drawer out to its stop. Reach underneath the front panel with both hands. There you will find the locking clips (catch couplings) on the left and right sides. Press the clip levers simultaneously inwards (towards the centre of the drawer) or forwards, depending on the exact design. This releases the drawer box from the runner. Slightly lift the drawer box at the front and slide it horizontally off the runners. Set the drawer safely aside.

2. Inspect the fixing method

Examine the exposed carcass runners inside the cabinet. Check which screws secure the runner to the carcass:

Euro screws: These feature a blunt tip, a coarse thread (usually 6.3 mm), and sit in pre-drilled 5 mm holes within the system hole line.
Chipboard screws: These feature a pointed tip, usually have a diameter of 3.5 mm or 4 mm, and are often driven directly into the wood without using pre-drilled 5 mm holes.

3. Remove the carcass runner

Begin dismantling the runner. Loosen the rear screws first and work your way forward. Support the runner with one hand whilst removing the final front screw. If the metal runner falls unsupported, it can scratch the interior finish or tear out the last screw hole through lever action. Repeat the process on the opposite side.

4. Measure for the replacement runner

To find the correct replacement fitting, determine the exact dimensions of the old runner. The most important metric is the nominal length (NL). Measure the length of the removed carcass runner in its closed state. Common sizes for kitchen units are 450 mm, 500 mm, or 550 mm.

Check also whether the previous hardware was a single extension (partial extension) or a full extension runner. A full extension runner pulls out 100%, whereas a single extension runner offers an extension path of roughly 75%. Measure the clear internal carcass depth (internal dimension from front edge to back panel) to ensure the replacement fitting fits properly.

5. Choose the runner functionality

Pay attention to the required closing mechanism when selecting your hardware. If the old runner had an integrated damping system, choose a replacement equipped with soft-close. This mechanism decelerates the drawer gently over the final centimetres and pulls it shut silently.

Important: Do not confuse soft-close with push-to-open. The push-to-open function (also known as tip-on) is designed for handleless drawer fronts, opening the drawer via light pressure on the front. Both systems use completely different mechanical components within the runner mechanism and cannot be interchanged unless using a dual-action specialised fitting.

6. Fit the new carcass runner

Position the new runner against the carcass side panel. Ideally, align it with the existing System 32 pattern (32 mm hole spacing, typically 37 mm setback from the front edge). Screw the runner horizontally into place. Ensure screw heads sit completely flush with the runner metal. A protruding screw head will obstruct the runner carriage.

7. Mount and engage the drawer box

Extend the carriages of the new runners fully forward. Place the drawer box horizontally onto the runners and push it smoothly back into the carcass. Over the final millimetres, the front locking clips will engage into the runner with an audible click. Test the movement by opening and closing the drawer multiple times.

Common Pitfalls and Installation Tips

Incorrect screw head: Using countersunk screws instead of pan-head screws on carcass runners often distorts the metal profile when tightened, causing the mechanism to bind.
Stripped screw holes: If old screws have torn out from the chipboard due to heavy loads, new screws will spin freely. Drill the hole out cleanly to 5 mm or 8 mm and glue in a matching wooden dowel. Once cured, drive the screw into the dowel. Alternatively, insert a threaded insert with a metric internal thread.
Incorrect load capacity: A wide kitchen pan drawer carrying heavy cookware requires high load capacity runners (e.g. 30 kg or 45 kg). Installing standard lightweight runners will lead to deformed profiles within a few months.
Out-of-square carcass: If the drawer binds despite new runners, the cabinet unit itself may be out of alignment. If the unit is not level and plumb, the carcass twists, meaning the internal width between runners no longer matches the drawer box. Level the cabinet precisely using the adjustable cabinet feet.

FAQ – Frequently Asked Questions

Can I easily replace a single extension runner with a full extension runner? Yes, this is mechanically possible in most cases provided there is sufficient internal cabinet depth. The nominal length (e.g. 500 mm) remains identical, though the screw hole pattern on the carcass side panel may differ and require new pilot holes. The wooden drawer box itself usually requires no modifications, provided the new front locking clips match.

How do I measure the nominal length correctly if the runner is broken? Measure the outer length of the wooden drawer box (excluding the applied front panel). For undermount runners, the drawer box depth corresponds exactly to the required runner nominal length. If the drawer box is 450 mm deep, you require a runner with a nominal length of 450 mm.

Why won't the drawer release from the runner when pressing the clips? Heavy dirt build-up, kitchen grease, or rust can seize the locking pins. Press the clip levers and gently wiggle the drawer box left and right whilst pulling forwards. Take care not to snap the plastic clips.

What screw length is ideal for carcass runners? For standard 16 mm thick chipboard carcasses, screws sized 3.5 x 15 mm or 4.0 x 15 mm are typically used. For 18 mm thick side panels, 17 mm long screws can be fitted. The screw must never pierce through the outside panel surface.

Matching Replacement Fittings for Your Project

Once removal is complete and exact measurements have been taken, suitable replacement hardware can be selected across the relevant product categories depending on drawer weight, required length, and functional mechanism (soft-close or push-to-open):

To maintain a concealed look underneath the drawer box: Undermount drawer runners
For complete access to the entire drawer interior: Full extension drawer runners
For quiet, cushioned drawer closing: Soft-close drawer runners
For handleless fronts opening via light pressure: Push-to-open drawer runners
For deep kitchen base units requiring a 50 cm depth: 500 mm drawer runners
For wide pan drawers requiring high weight capacities: Heavy-duty drawer runners
For traditional sliding mechanisms found in older furniture: Roller runner drawer slides