How to Repair Gas Struts: Step-by-Step Guide

August 3, 2026

A faulty gas strut cannot be mechanically repaired due to high internal pressure; it must be replaced with a component having an identical extension force in Newtons and a matching stroke.

When a kitchen wall unit flap no longer stays up or a living room cabinet lid slams shut uncontrollably, the problem is almost always the gas strut. This component consists of a sealed pressure tube and a piston rod. Inside, there is compressed nitrogen gas alongside a small quantity of oil for lubrication and end-position damping.

Much like a car tyre that loses tiny amounts of air over years, wear on the seals eventually causes the gas pressure to escape from these fittings. As a result, the required holding force is no longer achieved. Direct repair of the cylinder is impossible and extremely dangerous due to the high pressure. Repairing the furniture therefore consists of accurate diagnosis, restoring any torn mounting points in the timber, and properly replacing the strut.

This guide is aimed at fitters and ambitious DIYers, leading you through the process step by step.

Difficulty Level and Time Required

Difficulty: Easy to medium (if mounting points in the wood need repairing)
Time required: approx. 10 to 15 minutes per flap
People: 1 (a second person is helpful to hold the flap)

Tools and Materials Required

You do not need specialist tools to properly replace and repair the flap mechanism. Have the following ready:

Flat-head screwdriver (small, for releasing the retaining clips)
Cross-head screwdriver (PZ or PH drive, matching the fitted screws)
Rule or vernier caliper
New Gas Struts with the exact same Newton rating
Optional: Wood filler, wood glue, or a threaded insert if the screw holes in the cabinet carcass are stripped

Preparation: Determining the Correct Dimensions and Specifications

Before restoring the mechanism, you must check the parameters of the old fitting. Two values are mandatory here:

The extension force (N): The force of a gas strut is specified in Newtons. This value is almost always printed on the cylinder. Typical values for furniture are 50 N, 80 N, 120 N, or 150 N. For large fronts, specialist Gas Struts for Heavy Flaps with 250 N to 350 N are used. Never choose a stronger strut assuming it will last longer. A strut that is too strong will tear the hinges out of the wood; one that is too weak will not keep the flap open.
The total length (mm): Measure the strut in its fully extended state. The measurement is taken from the centre of the fixing eyelet (or ball socket) on one side to the centre of the eyelet on the other side. Common lengths in furniture construction range between 245 mm and 270 mm.

Step-by-Step Guide: Replacing Gas Struts

Replacement is standardised on most systems, as the struts generally sit on a ball stud.

Step 1: Secure the Flap

Open the cabinet door completely. Since the old strut no longer supports the weight, the flap must be propped up. It is best to work in pairs or support the front with a suitable wooden batten to prevent sudden falling and damage to the top concealed hinges.

Step 2: Remove the Old Strut

Most gas springs are fitted with ball sockets at the ends that sit on metal ball studs. These are secured by a small metal spring clip. Insert a flat-head screwdriver under this retaining clip and lever it slightly (about 2 mm to 3 mm is enough; it does not need to be completely removed). Now pull the strut off the ball stud with a gentle tug. Repeat this on the other side.

Step 3: Check Brackets and Screws

This is the most crucial step of the repair. Check the metal brackets screwed to the carcass wall and the front panel. Are the screws loose? Due to continuous leverage, chipboard screws (usually 3.5 mm or 4.0 mm diameter) frequently work loose. Tighten the screws hand-tight. If the screws spin freely, the wooden thread is stripped. How to fix this issue is explained in detail in the next main section.

Step 4: Clip in the New Strut

Take the replacement part. Pay attention to the correct installation orientation (see below). Simply press the ball socket of the new strut onto the ball stud of the bracket. The retaining clip usually does not need to be lifted for this; it engages audibly and noticeably with a click. To match the interior look of your cabinet, you can choose from various finishes when sourcing replacements, such as Gas Struts Silver, Gas Struts Black, or Gas Struts White.

Step 5: Function Test

Remove the support and move the flap up and down several times. It should open smoothly, travel automatically to the end stop in the upper third of its movement, and remain securely in position.

Deep Dive: Repairing Stripped Mountings in Wood

Often, it is not just the strut that is defective; the entire flap stay bracket has pulled out of the chipboard or MDF. Simply tightening the screws is no longer sufficient. To securely mount your Flap Fittings again with lasting pull-out resistance, you have three technical options:

Method A: Use larger screws If 3.5 mm diameter screws were previously fitted, use screws with a 4.0 mm or 4.5 mm diameter. Always pay strict attention to the length so the screw does not break through the exterior face of the front. For a standard furniture front thickness of 16 mm or 19 mm, screws of 13 mm to 15 mm length are the maximum.

Method B: Wood dowel repair Drill out the stripped hole with a wood drill bit to 6 mm or 8 mm (Caution: Do not drill right through! Use a depth stop). Put some wood glue into the hole and tap in a matching fluted wooden dowel. After the glue has cured, trim the protrusion flush. You now have solid wood again, into which you can pilot drill with a 2 mm bit and drive in the original screw.

Method C: Threaded inserts For a heavy-duty connection, drill out the hole and screw in a metal threaded insert. The strut bracket is then attached using a metric machine screw (e.g. M4) rather than a wood screw. This is the most professional solution for heavily used furniture.

Important Installation Rule: Fitting Orientation

A frequent mistake when installing gas springs is incorrect orientation. A gas strut must generally be installed so that the piston rod (the thinner, extendable part) points downwards when the flap is closed. The thicker pressure tube points upwards.

The reason for this is purely technical: inside the cylinder is a small quantity of oil. When the piston rod points downwards, the oil collects at the seal, keeping it supple and preventing gas from escaping prematurely. Furthermore, the oil in this position provides the desired end-position cushioning when the flap opens. If the strut is fitted upside down, the seal dries out and the component wears out significantly faster.

Common Mistakes During Repair

Avoid the following typical pitfalls when repairing your furniture flaps:

Replacing only one strut: If a flap is held by two struts, always replace both at the same time. Even if only one seems defective, the other will have already lost part of its pressure. A single new strut would have to bear the main load and would apply asymmetrical strain, warping the hinges.
Incorrect Newton rating: Switching from 80 N to 150 N simply so the flap holds better will mean the flap can barely be closed or will shoot upwards aggressively when opened.
Confusing strut types: A gas strut for holding flaps open is not a furniture damper (soft-close cylinder), which merely ensures the quiet closing of doors.

FAQ – Frequently Asked Questions

Can a gas strut be refilled? No. Furniture gas struts are sealed, maintenance-free systems under high pressure (often over 50 Bar). Drilling into or opening them is extremely dangerous. Defective cylinders must be replaced and disposed of via general waste or a recycling centre.

What does the specification "100 N" on the strut mean? The "N" stands for Newtons and indicates the extension force. Roughly converted, 10 N equals a lifting force of about 1 kg. A strut with 100 N can therefore support a weight of around 10 kg. However, because lever laws apply to furniture flaps, the flap weight does not translate 1:1 into Newtons.

How do I calculate the correct Newton rating if the print is illegible? If the old value can no longer be read, the force must be calculated. Weigh the furniture front (in kg) and measure the height of the front (in mm). A common rule of thumb for standard hinges is: (flap weight in kg x flap height in mm) / 13 = required force in N. Round the result up to the nearest available standard value (e.g. 80 N or 100 N).

Why can I not compress the new strut by hand? This is entirely normal. A strut with, for example, 150 N requires a pressure of around 15 kg to be compressed. With bare hands, without the leverage of the mounted cabinet flap, this is virtually impossible. Install the strut into the unit in its extended state; using the lever action of the flap, it will then compress without issue.