Install the new shock in the old strut’s mounting positions with the piston rod facing down, then test the lid for smooth operation.
Worn-down gas struts turn a one-finger toolbox lid into a heavy slam, and installing tool box shocks is a job most people finish in under ten minutes with basic hand tools. The task is simple because you are swapping a like-for-like part: the new strut bolts into the same brackets as the old one. The two details that decide success are matching the replacement to your original strut’s specs and getting the rod orientation right.
What You Need Before You Start
The install itself calls for almost no tooling. A flathead screwdriver or a socket wrench to release clips and fasteners, plus something to prop the lid open while you work. A helper or a temporary support rod keeps the heavy lid off your hands and protects the gas spring from lateral bending.
Matching the replacement is the step that prevents a wasted trip. Your new strut must match the old one’s extended length, force rating, and mounting style. If you are unsure what your lid needs, this tested tool box shock roundup explains how to pick the correct length and weight rating.
How to Install Tool Box Shocks Step by Step
Work one strut at a time on dual-strut systems, and always keep the lid supported. Tesla’s lift support procedure follows the same sequence you will use on a truck toolbox lid.
- Prop the lid open with a support rod or have a helper hold it securely.
- Release the old strut by prying off the wire clip or loosening the fasteners at each mounting point, then pull the fitting off the ball stud.
- Position the new strut with the piston rod facing down when the lid is closed.
- Push the end fitting onto the ball stud until it snaps; some fittings lock with a wire clip that you press into place.
- Repeat on the other end, then test the lid through a full open-and-close cycle.
When it works, the lid should stay up on its own and close with firm, controlled resistance. Tesla’s lift support replacement procedure highlights the same rod-down rule and the need for support while the old unit is out.
Fitting Tips and Common Mistakes
The rod-down orientation is the most important detail. Gas struts keep their internal seals lubricated by gravity, and installing one piston-up lets the seals run dry and fail early.
- Align the fitting squarely with the ball stud — forcing it sideways can bend the stud or damage the socket.
- Never use a hammer or vice grips on the end fittings; they snap on by hand pressure alone.
- On dual-strut lids, replace both units, one at a time, so the lid keeps balanced support.
- Keep the piston rod clean. Dirt, paint, or nicks on the shiny rod ruin the seal quickly.
End fittings come in two common designs. Knowing which one you have speeds up the removal step.
| Fitting Type | How It Attaches |
|---|---|
| Ball socket | Pushes onto the ball stud and locks with a spring clip inside the socket |
| Wire clip | Slides over the stud and uses an external C-shaped clip that you push down to hold it |
The mistake most people make is forcing a fitting that is not aligned. Line it up, push straight, and it clicks home.
FAQs
Which way do gas struts face on a toolbox?
Mount the gas strut with the piston rod facing down when the lid is closed. This keeps the internal oil coating the shaft seal, which prevents premature seal wear and leaks over time.
Can I replace just one toolbox shock?
Yes, but it is not recommended. A new strut pushes harder than its worn partner, so the lid will twist and open unevenly. Replacing both at the same time keeps the lid balanced and saves you from doing the job twice.
Why is my new shock hard to close?
The strut’s force rating is likely higher than your old one. Check the extended length and pound rating against your lid’s weight before buying. If the lid slams shut instead, the strut may be weak or installed rod-up.
References & Sources
- Tesla. “Lift Supports – Rear Closure” Service Manual. Details support-rod placement and rod-down orientation for strut replacement.