In brief
- A hood falling is not inevitable: gas struts lose pressure over time, especially in cold weather, and can be replaced in a few minutes if you are equipped correctly.
- Safety first : work in pairs, support the hood with solid support and remove/reassemble the cylinders one by one avoid injuries and dented hoods.
- Spring clips and ball joints : the vast majority of cylinders unclip from a spherical ball joint. Be careful, the ring can jump far; keep one hand on top when removing.
- Exceptions : some models are screwed (eyelet, M6/M8 screw) or incorporate an electrical cable (rare tailgates). Observe before buying to get the right reference.
- Price and choice : compare OEM and adaptable, check the force in Newton, the length and the type of tip. Sometimes the dealer is cheaper than a generic.
Practical: replacing bonnet struts, a discreet but essential repair for safety
Okay, we’ll see about that together. Hood struts, those little gas cylinders, work silently every time the hood is opened. Over the years, some of the gas escapes through the joints and the holding force decreases. When it is cold, the phenomenon increases and the hood tends to come down on its own.
Don’t panic, it’s simpler than it seems. Most recent cars and models up to 20 to 30 years old use these cylinders, especially on mid to high-end ranges. They are obviously found on almost all tailgates of SUVs, station wagons and minivans, but the hoods are also very often equipped with them, especially when they are heavy or phonetically insulated.
Why worry about it now that spring is coming back and the hood remains “pretty much” open? Precisely because gentleness cheats. At the next cold spell, the gas will contract and the drop in force will be felt suddenly. If you hear a small crack or see the hood lower a few centimeters before stopping, this is often a sign that the safety margin has already been used up.
A little mechanic’s advice: never trust “it’ll still hold a little”. A phone or a hand stuck between the hood and a radiator support can quickly ruin the day. A customer, Marc, thought he would be safe with his snow brush as a crutch. The hood slipped, the sheet metal deformed at the point of contact and he had to change the front grille; the price of the “economical” broom has turned into a hefty bill.
The first symptoms are quite clear. The hood no longer rises properly, the cylinder rod has a greasy veil, or a discreet whistle is heard at the end of the stroke. Sometimes, the car has taken repeated hits in winter, with snow and ice making everything heavier; the cylinders then worked well beyond their nominal load. Result: accelerated wear and loss of pressure.
Frankly, I have seen worse, but a preventive replacement before winter avoids unpleasant surprises. The operation is generally quick: we start by securing the cover, we unclip the old cylinders, we clip in the new ones, and that's it. The key is safety and observation, especially if the vehicle has an atypical assembly or a screwed ball joint that needs to be undone.
Another reassuring point: the cost remains reasonable. Adaptable cylinders are often very affordable, and on certain references, the manufacturer network offers competitive prices. This is what is recommended: identify the assembly, secure the cover and replace the pair, preferably in a single session. Peace of mind is priceless, and your noggin will thank you.
In summary, tackling the hood struts is a small, discreet repair that has a significant impact on safety. Refurbished, they make work under the hood much more pleasant and reliable.
Diagnosis of tired bonnet struts: simple and risk-free tests
Before taking out the tools, a good diagnosis avoids unnecessary purchases. The goal is to confirm that the loss of support really comes from the cylinders and not from a seized hinge or a poorly adjusted hood lock. No need for exotic equipment, just a little method and common sense.
Start with a visual inspection. Look for an oily film on the chrome rod or at the bottom of the cylinder; this is sometimes normal in very slight quantities, but a persistent black or greasy mark betrays a seal which allows gas and oil to pass through. Also check the ends: sometimes the ball joint is loose, giving the impression of a weak cylinder even though it is the fixing that is working.
Next, carry out a controlled opening test. Raise the hood by hand, stop halfway and release very gradually. If it goes down sharply or if you feel any bearings, the cylinders are on their knees. Repeat the hot engine and cold engine maneuver; at low temperatures, the available force decreases, which accentuates the defect. It may also be helpful toinspect the geometry to identify other potential issues.
A little mechanic’s advice: work in pairs. That’s what friends are for. One holds the hood with both hands, the other observes the symmetry of the movements. A cylinder that is weaker than the other causes the hood to “twist” by a few millimeters, an easy indicator to spot.
Another relevant test: the homemade stopwatch. From the hood almost closed to the open position, measure the time with constant hand pressure. A healthy set provides consistent progression. If the race is soft at the beginning then stiff at the end, or vice versa, there is an imbalance in pressure.
Safety actions to avoid bumps on the head
If the diagnosis confirms the weakness, secure immediately. Improvise a “clean” support: a telescopic bar, a sturdy handle with a rubber tip, or a crowbar protected by a thick cloth. Avoid smooth or too short supports which can slip.
Never lean under a hood that does not hold on its own, even for “two seconds”. A gust of wind or a slight shock and the hood falls. If you hear this noise, a sharp click in the middle of the stroke, it is often a sign that the hinge is compensating for the weakness of the cylinders and that the test must be stopped.
Differentiate a weak actuator from a hard cover
A strong cover can come from a crushed rubber seal, a dry hinge or a lock that is too high. Lightly grease the pivots and check the alignment of the hook; if the opening becomes fluid but the cover still does not hold, the diagnosis falls on the cylinders. Conversely, if oil and cleaning change behavior, consider adjustment before replacement.
To get a clear idea of the gestures, a video demonstration helps visualize the clips and temporary presses.
Once the diagnosis has been made, it is time to prepare for the replacement by choosing the right tools and the right method. The objective is to work cleanly and gain confidence for the future.
Replacing tired bonnet struts step by step: tools, methods and mistakes to avoid
The procedure is simple if you respect the order of operations. The idea is to never find yourself with a hood without assistance and without support. We therefore replace one cylinder at a time, keeping the hood securely in place.
Useful tools for hassle-free replacement
- Thin flat screwdriver for prying the spring ring.
- Needle-nosed pliers to recover a stubborn clip.
- Support bar or protected crowbar, to support the cover.
- Thick cloth to avoid marks under the hood.
- Gloves and glasses to protect yourself from popping clips.
Start by positioning the temporary support on the side opposite the first cylinder to remove. Ask a friend to hold the hood, or check that the support is properly positioned against a rigid area (wing edge, hood reinforcement). Some of the weight is still carried by the old cylinders, but this should not be counted on.
Observe the end piece on the wing side and on the hood side. The most common configuration is a spring clip clipped onto a ball joint. Insert the flathead screwdriver under the lip of the ring, pull lightly to release pressure, then gently pry to disengage. Put your hand over the ring: it can fly surprisingly far.
Mechanics is like grammar, there are always exceptions. Some models use a screwed eyelet with a small M6/M8 screw or ball joint that unscrews from the bracket. In this case, hold the ball joint with a spanner while unscrewing the central screw so as not to tear off the paint or chisel the base.
Install the new cylinder in the same direction as the old one. Typically, the cylinder goes up and the rod goes down, which keeps the seal lubricated. Align the tip and press firmly with your thumb to clip onto the ball. If it resists, spread the ring very slightly with the screwdriver, but without removing it entirely so as not to lose it.
A little mechanic’s advice: first present the end that is easiest to access, then “adjust” the other by very slightly adjusting the height of the cover. Never force twisting on the chrome rod; a micro-scratch and the seal will wear prematurely.
Repeat the same operation on the other side. Once the pair is in place, remove the support, raise and lower the hood two or three times to check fluidity and balance. If a crack is heard, check that the clips are securely locked and that nothing is rubbing against the hood reinforcement.
On a utility vehicle that came to the garage, one of the ball joint supports was slightly twisted. The hood closed, but the cylinder rubbed 5 mm. A simple straightening of the support solved the problem. Moral: always inspect the geometry, especially after a light impact or bumper replacement.
Last point: if the car has a very heavy hood, do not hesitate to retain the help of a second person until the last clicks. Better a minute of reinforcement than pinched fingers. Once validated, the cover must hold open without hesitation and rise with a clear but controlled movement.
Special cases and pitfalls to avoid when fitting new bonnet struts
Some cars have surprises in store. The important thing is to know how to anticipate them to stay calm. This is what is recommended to avoid the most frequent pitfalls.
Corrosion and seized fasteners
On vehicles exposed to salt, it happens that the ball joint or the retaining screw is welded by rust. Soak the day before with a penetrating penetrating oil, hold the ball joint with a wrench and loosen without forcing “across”. If the support base breaks, change the support rather than tinkering; a ball joint that wanders ends up marking the sheet metal.
Rare electrical fittings on tailgates
On certain tailgates, an integrated defroster or light wire passes along a cylinder. Place it carefully and mark the route to reassemble it identically. On an engine hood, this is extremely rare, but still check the presence of proximity sensors before pulling.
Active covers and compatibilities
The pedestrian protection system (active cover) is generally not linked to the opening cylinders. We change these when they are weak, period. If in doubt, follow the manufacturer's procedure to avoid disturbing a sensor or hinge pretensioner. On recent models, such as some electric ones, the official recommendation is clear: remove and reinstall one cylinder at a time.
Orientation, firmness and closing of the hood
A new cylinder can make the closure a little more “firm”. Nothing abnormal: the pressure has returned to the nominal value. Sometimes you have to slam the hood a little more firmly, especially on models where the addition of jacks was optional. If you hear this noise, a bounce and non-locking, lower the hood 20 cm and release it suddenly, without accompanying it.
Never oil the chrome rod. Any grease attracts dust, which wears down the seal. Simply clean with a soft cloth if necessary. And do not reverse high/low: the cylinder at the top improves lubrication and longevity.
To visualize these particularities, another video demonstration allows you to identify at a glance the screw systems, the clips and the correct orientation.
With these precautions, special assemblies and small adaptation differences are no longer scary. Assembly remains simple, as long as you remain methodical and never remove both cylinders at the same time on a heavy hood.
Choose and buy bonnet struts in 2026: prices, references and guarantees
Between manufacturer and adaptable parts, the offer is wide. The goal is not to pay the most, but to choose a reference compatible in strength, length and tips, with a correct guarantee. A quick overview helps you decide.
Essential selection criteria
- Force (N) : must correspond to the origin. Too weak, the hood falls; too strong, the hinges suffer.
- Closed and open lengths : a difference of a few millimeters can change the opening angle.
- Type of end piece : 10 mm ball joint, screwed eyelet, specific thread. Observe before buying.
- Sealing quality : hard chrome rod, treated joints, possibly stainless steel for saline climates.
- Guarantee and availability : being able to exchange quickly in the event of a defect is a real plus.
On the budget side, there are surprises: certain dealerships offer packs at competitive prices, especially on models released. Conversely, on rarer vehicles, the adaptable becomes very attractive and just as durable if the reference is well chosen.
| Type of cylinder | Average price (pair) | Advantages | Disadvantages | When to choose |
|---|---|---|---|---|
| Manufacturer (OEM) | 60 € – 160 € | Perfect compatibility, finish at the original level, network guarantee | Price sometimes high, delays on rare models | If you want “plug and play” and an opening identical to new |
| Premium adaptable | 40 € – 100 € | Good quality/price ratio, wide choice, stainless steel options | Requires checking strength and bits, summary instructions | Daily use, varied climate, controlled budget |
| Entry-level adaptable | 25 € – 50 € | Very economical, immediate availability | Quality variability, uneven longevity | Quick repair or near resale |
Before purchasing, measure the old cylinder from end to end closed, then open if possible. Note the engraved references and the diameter of the ball joint. Take a photo of the media to check in store or online. Finally, buy in pairs: mixing an old one and a new one creates an imbalance and tires the hinge.
What you need to remember: choosing wisely means avoiding double purchases and guaranteeing smooth opening/closing. With the correct reference, assembly takes a few minutes and security instantly returns to the original level.
Do you always have to change both hood struts at the same time?
Yes. A new cylinder is firmer than an old one and would create an imbalance. Changing the pair guarantees symmetrical opening and avoids tiring hinges and supports.
How to hold the hood during the procedure if no one is available?
Use a fairly long rigid bar wedged between a hood reinforcement and a solid engine bay area, with a cloth to protect the paint. Check stability before approaching the clips.
In which direction should the cylinder be mounted?
In most cases, cylinder up and rod down to ensure seal lubrication. Reproduce the original direction observed during removal.
A clip jumped and got lost: can we ride like that?
No. The clip locks the tip onto the ball joint. Without it, the tip may come loose when opening or while rolling. Replace the clip with the correct part or the complete cylinder if the part is not sold separately.
Why is the hood harder to close after replacement?
New cylinders have the nominal pressure. The hood may require a more straightforward movement to clip the lock. This is normal if alignment is correct and no abnormal friction is present.