Quick Info
Model
450, 452
Estimated Cost
€15 – €30
Difficulty
Beginner
Time Required
15 Minutes
Safety Notes
The "Heavy Hood" Warning: The front hood of the Roadster is surprisingly heavy when not supported. Do not attempt this alone unless you have a sturdy prop rod or a second person to hold the hood up. If the hood falls while a strut is removed, it can cause injury or damage the plastic body panels.
Spring Tension: The metal retaining clips on the struts are under tension. When prying them with a screwdriver, they can occasionally fly off. Wear eye protection to stay safe.
Ball Joint Integrity: Inspect the metal ball studs on the car's body. If they are rusted or loose, clean them with a wire brush before installing the new lifters.
Step-by-Step Guide
Introduction
The Smart Roadster’s front hood (or "boot") relies on two pressurized gas struts to counteract gravity. As these cars age, the gas inside the cylinders slowly leaks past the rubber seals. You will first notice the failure on cold mornings—the hood might stay up for a few seconds and then slowly descend onto your head while you are reaching for your bags. Eventually, they will fail completely, requiring you to manually hold the hood open with one hand while working with the other.
Replacing these lifters is one of the easiest DIY tasks you can perform, yet it makes the car feel significantly more premium. High-quality aftermarket lifters often provide slightly more pressure than the original factory units, ensuring that the hood "pops" open eagerly and stays rock-solid even in windy conditions. This guide covers the front installation, but the same logic applies to the rear glass hatch or engine cover struts as well.
Securing the Hood
Open the front hood fully. Since you will be removing the support, you must have a helper hold the hood at its maximum height, or use a piece of wood or a telescoping rod to prop it open securely.
Never rely on one old strut to hold the hood while you remove the other.
Releasing the Retaining Clips
Locate the metal "C-clip" or band on the head of the old strut (where it attaches to the ball joint).
Insert a small flathead screwdriver under the clip and pry it outward about 5mm.
You do not need to remove the clip entirely—just enough to release the tension on the ball.
Removing the Old Struts
With the clip pried back, pull the head of the strut away from the ball stud.
It should pop off with minimal effort.
Repeat this for both the top and bottom attachments of the strut.
Once the first strut is off, your helper will feel the full weight of the hood, so be prepared.
Preparing the New Struts
Check your new struts. Most come with the clips pre-installed in the "locked" position.
You do not usually need to pry the clips on the new units to install them.
Simply align the socket of the new strut with the ball stud on the car.
Snapping the New Struts into Place
Push the socket firmly onto the ball stud until you hear a distinct "click" or "thud."
This indicates that the internal spring has locked around the ball. Give it a firm tug to ensure it is locked. Tip: Install the bottom joint first, then align the top. If the strut is slightly too long, have your helper lift the hood slightly higher to match the holes.
Once both struts are installed, slowly lower the hood to ensure there is no interference. Let the hood go from the halfway point—it should now stay open on its own or even rise slowly. Open and close it a few times to distribute the internal lubricant in the new cylinders.
