You notice it the first time when the boot taps you on the shoulder instead of lifting cleanly. Then a few days later, it will not stay up at all. If you are asking, “why is my boot strut not working”, the short answer is that the strut has usually lost pressure, worn out internally, or is being affected by damage, fitment issues, or weather.
A failing boot strut is more than an inconvenience. It makes loading shopping, sports gear, prams, tools, or luggage harder, and it can turn into a safety issue quickly. The good news is that the cause is often straightforward, and in many cases the fix is simply replacing the struts with the correct pair.
Why is my boot strut not working in the first place?
Boot struts are petrol-charged supports designed to help lift and hold the boot open. Over time, the internal petrol pressure drops, seals wear, and the strut loses the force it needs to do its job. That is the most common reason they stop working properly.
But it is not always just age. Sometimes the struts are still partly functional, yet the boot feels heavy, opens unevenly, or drops in cooler weather. In those cases, the issue may be a mix of wear, installation problems, or extra weight on the boot lid.
The main causes tend to be fairly practical. Old struts lose their lifting strength. Damaged shafts or seals let pressure escape. Incorrect replacement struts may be the wrong length or force rating. Hinges can bind and add resistance. In some vehicles, spoilers, accessories, or previous repairs can change the weight balance enough to make a marginal strut fail sooner.
The most common reasons boot struts fail
Normal wear and tear
Like wiper blades and batteries, petrol struts are service items. They do not last forever. Every time you open and close the boot, the seals and internal components work a little harder. After years of use, they lose pressure and cannot support the lid properly.
If your car is older and the struts have never been replaced, wear is the first thing to suspect.
Loss of petrol pressure
Boot struts rely on compressed petrol to provide lifting force. When that pressure drops, the strut may still look fine on the outside, but it will no longer hold the boot open. This is one of the most common failure points because it can happen gradually, making it easy to ignore until the boot becomes obviously heavy.
Damaged seals or rod surface
If the rod is scratched, bent, or dirty, the seal can wear out faster. Once the seal is compromised, petrol can leak and performance drops. In some cases, you may notice oil residue around the strut body, which is a sign the unit is failing internally.
Cold weather performance
Petrol struts can feel weaker in colder conditions. In South East Queensland this is usually less dramatic than in cooler parts of Australia, but even mild temperature changes can make a worn strut more noticeable. If your boot works fine in the afternoon but struggles in the morning, the struts may already be near the end of their life.
Added weight on the boot lid
A rear spoiler, accessories, or non-standard fittings can increase the weight the struts need to lift. If the struts were only just coping before, that extra load can push them over the edge. This also matters after accident repairs if the boot lid alignment or weight has changed slightly.
Incorrect replacement struts
Not all struts are interchangeable, even if they appear similar. If the wrong part has been fitted, the boot may not open fully, may lift too fast, or may not stay open at all. Length, end fittings, and pressure rating all matter.
Signs your boot struts are on the way out
Most boot struts do not fail all at once. They usually give you a few warnings first.
The most obvious sign is a boot that will not stay open on its own. You might also notice it rising slowly, stopping halfway, or needing a push to get started. Some boots drop faster than they should, which can catch you off guard.
Uneven lifting is another clue. If one side feels like it is doing more work than the other, one strut may be weaker than its pair. In practice, that is why both struts are usually replaced together. Fitting one new strut next to one tired strut can leave the boot operating unevenly.
You may also hear creaking or feel stiffness around the hinges. Sometimes that points to hinge resistance rather than the strut alone, and that is worth checking before assuming the petrol struts are the only problem.
Can you fix a boot strut, or do you replace it?
In most cases, a failing boot strut is replaced rather than repaired. These units are sealed, and once they lose pressure or the internal seal wears out, repair is usually not practical or cost-effective.
That is actually good news for most owners. Replacement is generally straightforward when the right parts are used, and it restores safe, consistent operation without the trial and error of trying to revive worn components.
What matters is getting the right struts for the vehicle and fitting them correctly. A cheap or generic option that does not match the original specification can leave you with the same problem, only sooner.
When the problem is not the strut itself
Hinge or alignment issues
If the boot hinges are stiff, damaged, or slightly out of alignment, the struts have to work harder than they should. That extra resistance can make a good strut seem weak. It can also shorten the life of new struts if the underlying issue is not addressed.
Body or repair-related changes
After rear-end repairs, panel adjustment can affect how the boot opens and closes. Even a small misalignment changes the load on the struts. If the problem started after bodywork, it is worth considering whether the struts are the real fault or just reacting to a changed setup.
One failed strut, one tired strut
Sometimes only one side has clearly failed, but the other is not far behind. Replacing just one may seem cheaper in the moment, but it often leads to uneven pressure and shorter service life. For balance and reliability, pairs are usually the smarter option.
Should you keep using the boot if the struts are failing?
You can, but carefully. A weak boot strut is not just annoying. It creates a real risk of the boot lid falling unexpectedly while you are loading or unloading the car. That is especially frustrating when your hands are full, but it can also cause injury or damage.
If the boot is already dropping on its own, do not assume it will stay up “just this once”. Failing struts are unpredictable near the end of their life. The safer move is to have them checked and replaced before they stop working completely.
What to expect from replacement boot struts
A proper replacement should make the boot feel lighter, smoother, and more secure. It should open with controlled movement and stay up without drifting down. It should also close normally, without needing excessive force.
There is a balance here. Struts that are too weak will not support the boot, but struts that are too strong can put extra stress on hinges and mounting points. That is why correct specification matters more than simply choosing the stiffest option available.
For everyday drivers, convenience is part of the value too. Having the job handled by an experienced mobile service means you do not have to spend your day in a waiting room for a problem that is usually quick to sort out. That is one reason many vehicle owners in Brisbane choose services like VIP Car Care when their struts start failing.
Why is my boot strut not working after replacement?
If new struts still are not performing properly, the usual causes are incorrect part selection, worn hinges, poor installation, or an unaddressed alignment issue. It is also possible that the boot lid has extra weight the standard struts were not designed to handle.
That is why diagnosis matters. Replacing struts should solve the problem, but only if the struts were the real problem and the new parts are matched correctly to the vehicle.
A boot should open reliably without becoming a two-handed wrestling match. If yours is sagging, heavy, or dropping unexpectedly, it is usually a sign that the struts have reached the end of their service life and need attention sooner rather than later. Getting on top of it early keeps the car safer, more practical, and much less frustrating to live with.