A boot lid that slowly sinks while you are loading groceries is more than an annoyance. It can become a safety issue quickly. If you are asking, “when should gas struts be replaced?”, the simple answer is when they can no longer hold and control the panel they support reliably. The better answer is to look for the early warning signs before a heavy bonnet, tailgate or boot lid catches you by surprise.

Gas struts are fitted to many vehicles to make opening and holding panels feel easy. They work under pressure, so when their internal seals wear or the gas charge reduces, their lifting strength fades. Replacing them at the right time keeps everyday use safe, convenient and kinder to your vehicle’s hinges and mounting points.

When should gas struts be replaced?

Gas struts should be replaced when they no longer keep the bonnet, boot, tailgate, rear window or other supported panel open without assistance. A strut does not have to be completely flat to be due for replacement. Reduced lifting power, inconsistent operation and visible damage are all good reasons to arrange a replacement.

The most common sign is a panel that will not stay up. You may lift the boot normally, only for it to drift down or fall without warning. On a tailgate, you might notice that it needs a firm push to reach the fully open position, or that it only stays open on level ground. These are clear signs the struts are losing pressure.

Look out for these other symptoms as well:

• The bonnet, boot or tailgate feels noticeably heavier to lift than it once did.
• The panel rises slowly, unevenly or needs help to reach its open position.
• One side opens higher or feels stronger than the other.
• There is oil residue around the strut shaft or body, corrosion on the rod, or damage to the mounts.
• The strut rod is bent, scratched or pitted, or the fitting points are loose.

Do not assume a strut is fine simply because it holds the panel open for a moment. A weak strut can fail with vibration, wind, a sloping driveway or the extra weight of rain on a tailgate. If you have to use a broom handle, prop rod or one hand to keep a panel up, it is time to have the struts assessed.

A sudden drop needs prompt attention

A panel that drops suddenly is a more urgent warning. Never place your hands, head or body beneath a bonnet or tailgate that is not properly supported. This is particularly relevant for family vehicles, SUVs and utes, where a large tailgate can be heavy and awkward to control.

Until the struts are replaced, use the vehicle carefully and support the panel with a suitable fixed prop if one is available. Avoid relying on improvised supports that can slip on a driveway or footpath.

Why gas struts lose their strength

Gas struts are sealed units filled with pressurised gas and a small amount of oil for lubrication and damping. Over time, seals naturally wear and a small amount of gas can escape. The result is lower extension force and less ability to hold a panel at full height.

Age is part of the picture, but it is not the only factor. Australia’s heat, strong sun, dust, coastal salt and frequent use can all shorten the useful life of gas struts. A vehicle parked outdoors for years may need replacement sooner than one kept under cover, while a family SUV with a tailgate opened many times each day will put more cycles through its struts.

Physical damage also matters. A scratched or rusty shaft can damage the internal seal each time the strut moves. Bent struts, worn ball joints and loose brackets can affect how the panel opens and closes, even if the gas charge is still reasonable. For that reason, a proper inspection should consider the complete mounting arrangement, not just whether the strut feels weak.

A simple way to check your car’s struts

With the vehicle parked safely on level ground, open the relevant panel as you normally would. It should lift smoothly, reach its intended open position and remain there without you holding it. Close it, then repeat the test a few times.

Pay attention to consistency. A weak gas strut may seem acceptable after the vehicle has been sitting in warm weather but struggle on a cool morning. Temperature changes can make an already tired strut more obvious, because gas pressure naturally changes with temperature.

Avoid testing by pulling hard on the strut rod, puncturing the unit or applying lubricant to the rod. Gas struts are pressurised components, and the wrong treatment can create a safety risk or make the issue worse. If you see leaking fluid, corrosion or damage, professional replacement is the sensible option.

Should both gas struts be replaced together?

In most cases, yes. Bonnet, boot and tailgate struts are designed to work as a matched pair. If one has weakened through normal age and use, the other is usually not far behind. Replacing both helps the panel lift evenly and prevents the new strut from carrying most of the load.

There are exceptions. If a single strut has been damaged by an impact while the other is relatively new, replacing only the damaged unit may be appropriate. The key is matching the specification exactly, including the length, end fittings and force rating.

Fitting a strut that is too weak can leave the panel unsafe and difficult to use. Fitting one that is too strong is not a better fix. Excess force can make closing difficult and place unnecessary load on hinges, brackets and the panel itself. Vehicle-specific parts and correct installation matter.

Why professional fitting is worth it

Replacing gas struts may look straightforward, but a bonnet or tailgate needs to be securely supported while the old units are removed. Incorrect fitting can damage clips, mounts or paintwork, and a poorly supported panel can cause injury.

A trained technician can identify the correct struts for your vehicle, inspect the mounting points and fit the pair safely. They can also check that the panel opens smoothly, reaches the correct height and closes without undue force. This is especially useful for heavier SUV tailgates, rear glass windows and custom-fitted accessories that may alter the load a strut needs to carry.

For busy Australian vehicle owners, mobile replacement also removes the need to drive around with a failing boot or bonnet. VIP Car Care provides professional gas strut replacement with the convenience of service at a location that suits you, helping keep essential vehicle maintenance simple and affordable.

Do not wait for a complete failure

Gas struts rarely improve once they begin to weaken. Waiting until a tailgate falls or a bonnet will not stay open can turn a small maintenance job into an inconvenient and potentially unsafe problem. Replacing tired struts early gives you a panel that feels controlled, secure and easy to use every day.

If your bonnet, boot or tailgate is heavier than it used to be, book an inspection before it becomes a problem. A properly supported panel is one of those small details that makes your vehicle safer, more practical and better cared for.