Replacing a gas strut takes about 15 minutes and needs no special tools: measure the old strut fully extended, match its length, force and end fitting, then swap it with the lid safely propped. This guide walks through each step.
What you need
- A tape measure
- A flat screwdriver (for ball socket clips)
- A prop to hold the lid open safely
- The replacement strut — same extended length, force and fitting type
Step 1: Read or measure the old strut
Most struts have the specification printed on the tube, for example "485 N" and a part number. If the print has worn off:
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Extended length: measure eye-to-eye with the strut fully extended.
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Stroke: measure the visible piston rod length.
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Force: if unknown, estimate from the lid weight (see our choosing guide) or match a similar application.
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Thread/fitting: ball sockets are marked M6, M8 or M10 — measure the thread diameter (6, 8 or 10 mm) if unsure.
Step 2: Support the lid before removing anything
Never rely on the old strut to hold the lid while you work. Prop the lid with a solid support — a length of timber works well. On vehicles, have a second person hold the tailgate.
Step 3: Remove the old strut
For ball socket fittings, slide a flat screwdriver under the retaining spring clip on the end fitting and lift it about 2 mm — the socket then pulls straight off the ball stud. Do the piston-rod end first, then the cylinder end. For eyelet fittings, undo the through-bolt.
Step 4: Fit the new strut
- Fit the cylinder (thick tube) end up and the piston rod down — this keeps the seals lubricated and roughly doubles service life.
- Press ball sockets onto the studs until the clip snaps — no tools needed.
- Open and close the lid fully a few times to check clearance through the whole travel.
Common mistakes to avoid
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Replacing only one of a pair. The old strut has lost force — the mismatch twists the lid. Always replace struts in pairs.
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Choosing a stronger strut to "fix" a heavy lid. If the geometry was right before, match the original force; excessive force strains hinges and makes closing difficult.
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Ignoring the compressed length. The new strut must fit between the mounts with the lid closed — check compressed length, not just extended length.
When to replace rather than repair
Gas struts are sealed pressure vessels and cannot be refilled safely at home. If a strut has lost force, leaks oil or is bent, replace it. With prices from around £20 and automatic quantity discounts from 2 units, replacement is the economical option.
Find your size in our gas strut range — filter by length, thread and force, with UK-wide delivery.
