Vehicle lift supports are the quiet, hardworking components that make accessing your trunk, hood, or tailgate effortless. Often called gas struts or gas springs, these pressurized cylinders hold heavy panels open so you can load groceries or check your engine safely. When they begin to wear out, they can become a significant inconvenience or even a safety hazard.
Understanding how lift supports work and knowing when to replace them is a fundamental part of vehicle maintenance. Replacing them is a task most car owners can complete in under twenty minutes with minimal tools. This guide will walk you through everything you need to know about vehicle lift supports, from identifying failure to performing a successful DIY installation.
What Are Vehicle Lift Supports?
A vehicle lift support is a hydropneumatic energy storage device. It consists of a narrow rod that moves inside a larger cylinder filled with pressurized nitrogen gas and a small amount of oil. The gas provides the lifting force, while the oil provides lubrication and dampens the movement at the end of the stroke.
These components are designed to handle specific weights. For example, the lift supports for a heavy SUV tailgate are much stronger than those used for a small sedan’s trunk. They are usually found in pairs, working together to balance the weight of the moving part of the vehicle.
Beyond trunks and hoods, you may find lift supports on rear glass windows, truck bed covers, and even toolboxes. While they are built to last for several years, the internal seals eventually degrade, leading to a loss of pressure and functionality.
Common Signs of Failing Lift Supports
The most obvious sign of failure is a trunk or hood that will not stay open. However, there are several early warning signs that indicate your lift supports are nearing the end of their lifespan. Identifying these early can prevent the panel from falling unexpectedly.
- Gradual Drooping: You may notice the hatch stays open at first but slowly begins to sink after a few minutes.
- Difficulty Opening: If you find yourself putting significantly more physical effort into lifting the trunk or hood, the gas pressure has likely decreased.
- Sensitivity to Cold: Gas contracts in cold temperatures. If your lift supports work in the summer but fail in the winter, the seals are likely worn out.
- Visible Leaking: If you see oily residue around the piston rod or the cylinder, the internal seals have failed, and the support should be replaced immediately.
- Unusual Noises: A scraping, hissing, or clicking sound during operation often indicates internal damage or a lack of lubrication.
Why Do Lift Supports Fail?
Lift supports are subject to constant pressure, even when they are not in use. Over time, the rubber seals inside the cylinder naturally harden and crack. This allows the pressurized nitrogen gas to slowly leak out, reducing the support’s ability to hold weight.
Environmental factors also play a role. Extreme heat can cause the gas to expand and put extra stress on the seals, while extreme cold can cause the seals to shrink and leak. Dust, salt, and road debris can also scratch the piston rod, which then damages the seals as the rod moves in and out.
Finally, frequency of use is a factor. Every time you open your trunk, the lift support completes a cycle. Most supports are rated for a specific number of cycles, and once that limit is reached, the internal components simply wear out.
How to Choose the Right Replacement
When it comes to buying new lift supports, accuracy is essential. You cannot simply use any strut that looks like it might fit. Using a support with too much pressure can damage your vehicle’s hinges, while one with too little pressure will fail to hold the panel open.
The easiest way to find the correct part is to look for a part number printed directly on your current lift support. Most manufacturers include a long string of numbers and letters on the cylinder. Searching for this number online or at an auto parts store is the most reliable method.
If the part number is missing or unreadable, you will need to know your vehicle’s make, model, year, and trim level. Be aware that some models have different lift supports depending on whether the vehicle has a spoiler or a rear wiper, as these add extra weight to the hatch.
You can also measure the support if necessary. You will need the “extended length” (measured from the center of one mounting point to the other when fully open) and the “compressed length.” However, using the vehicle’s specific application data is always preferred over manual measurements.
Tools Needed for Replacement
One of the best things about replacing lift supports is that it requires very few tools. Most modern vehicles use a “ball and socket” mounting system that is held in place by a small metal retaining clip.
- A Small Flat-Head Screwdriver: This is used to pry up the retaining clips on the old supports.
- A Prop Rod or Helper: You must have something to hold the hood or trunk open while you remove the old supports. A piece of wood or a sturdy broomstick can work, but a second person is much safer.
- Clean Cloth: To wipe away any old grease or dirt from the mounting studs.
- Safety Glasses: To protect your eyes from any debris or accidental releases of pressure.
Step-by-Step Replacement Guide
Before you begin, ensure you have the correct replacement parts. It is highly recommended to replace lift supports in pairs, even if only one seems to be failing. If one has failed, the other is likely close behind, and a new support paired with an old one can cause the panel to twist or hinge unevenly.
Step 1: Secure the Panel
Open the trunk, hood, or hatch fully. Have your helper hold it securely, or place your prop rod in a stable position. Never rely on the old lift supports to hold the weight while you are working on them. These panels are heavy and can cause serious injury if they fall.
Step 2: Locate the Retaining Clips
Look at the ends of the lift support where it attaches to the vehicle. You will see a small metal band or clip wrapped around the socket. This clip locks the socket onto the ball stud on the vehicle’s frame.
Step 3: Remove the Old Support
Insert the tip of your flat-head screwdriver under the metal clip. Gently pry the clip outward just enough to release the tension. You do not usually need to remove the clip entirely. While holding the clip out, pull the socket away from the ball stud. Repeat this for the other end of the support.
Step 4: Clean the Mounting Studs
Use a clean cloth to wipe away any old grease, dirt, or rust from the ball studs on the vehicle. This ensures a smooth fit for the new part. Some new lift supports come with a small amount of grease already inside the socket; if not, you can apply a tiny dab of multi-purpose grease to the ball stud.
Step 5: Install the New Support
Most new lift supports are designed to “snap” into place. You generally do not need to pry the clips on the new supports. Simply align the socket with the ball stud and press firmly until you hear a click. Ensure the rod end and the cylinder end are oriented the same way as the original (usually with the cylinder at the top).
Step 6: Test the Operation
Once both sides are replaced, remove your prop rod or have your helper let go. Gently lower the panel to ensure it closes smoothly, then open it again to confirm it stays up on its own. The movement should be controlled and quiet.
Safety and Maintenance Tips
To get the longest life out of your new lift supports, keep the piston rods clean. If you live in an area with road salt or heavy dust, wipe the rods down occasionally with a soft, dry cloth. Avoid using lubricants or cleaners on the rods, as these can actually attract dirt and damage the internal seals.
Always avoid “helping” the lift supports by forcing the trunk or hood open faster than it wants to go. This puts unnecessary pressure on the seals. Similarly, do not leave the trunk or hood open for extended periods (days or weeks) if it can be avoided, as this keeps the internal spring under constant extension.
Finally, never attempt to open or puncture a lift support cylinder. They contain gas under extremely high pressure and can be very dangerous if tampered with. Dispose of your old supports according to local regulations, usually by taking them to an auto parts store or recycling center.
Maintaining your vehicle’s lift supports is a simple way to ensure your car remains functional and safe. By spending a few minutes on this DIY task, you can avoid the frustration of a falling trunk and keep your vehicle operating like new. For more practical automotive advice and home maintenance tips, explore our other helpful guides on SearchAndHelp.com.