Your Hood or Trunk Won’t Stay Up? Don’t Get Brained — Replace Those Lift Supports
Twenty years ago a guy comes into the shop with a knot on his forehead the size of a golf ball. His hood struts had been weak for six months, he’d been using a broomstick to prop it open, and one day the stick slipped while his head was under there. Hood came down like a guillotine. Four stitches and a concussion. All because he wouldn’t spend thirty bucks on new lift supports.
I tell that story every time somebody walks in holding their hood open with one hand. These things are cheap, they’re easy to replace, and there is zero excuse for getting hurt over worn-out gas struts. So let’s talk about what you need to measure, how to pick the right ones, and how to swap them out in about fifteen minutes.
What Actually Goes Wrong with Lift Supports
Inside every lift support there’s nitrogen gas under pressure pushing a rod out of a sealed cylinder. Over time — and it’s almost always time, not mileage — that gas leaks past the seals. When enough leaks out, the strut can’t hold the weight anymore. You’ll notice it first on cold mornings. Gas contracts when it’s cold, so a strut that barely hangs on in July will straight-up quit in January.
The other thing that kills them is heat. Hood struts on anything with a big engine sit right above the exhaust manifolds. That heat cycling bakes the seals brittle. I’ve seen Explorers and Tahoes go through hood struts faster than brake pads.
How to Measure What You Need
Don’t just punch your car into some website and hope it’s right. I’ve seen fitment guides get it wrong plenty of times — or you’ll get a strut that technically “fits” but has way less force than the factory spec, and now your trunk is drooping again two months later. Take thirty seconds and measure what’s on the car. Here’s what matters:
Extended length. Prop the hood or trunk all the way open. Measure center of the top ball socket to center of the bottom ball socket. That’s your extended length. Too short and your lid won’t open all the way. Too long and you’ll never get it closed without bending something.
Compressed length. This is how short the strut gets when it’s fully squeezed. If it’s too long, the strut bottoms out before your trunk latches, and you’ll either dent the quarter panel trying to force it or crack the mounting bracket. Usually you can trust the compressed length on a part that matches your extended length, but if you’re dealing with some weird application, measure it closed.
Force rating. Look on the old strut — there’s almost always a label printed right on the body. You’ll see something like “400N” or “0450N.” That’s Newtons. Divide by 4.45 to get pounds-force (roughly). A 400N strut pushes about 90 lbs. If you’re shopping and see struts listed in pounds instead of Newtons, same thing in reverse.
If the label’s worn off or painted over, you’re going to have to look up your specific vehicle. Aftermarket struts get the force rating close to factory spec, but here’s the thing: if you added a spoiler to your trunk lid or sound deadening to your hood, the factory force rating might not cut it anymore. You’ll want something a notch stronger.
End fittings. Nearly everything uses a 10mm ball socket. Pop one end off and look — it’s just a metal cup that snaps over a little ball stud welded to the body. Some older imports used eyelet ends or different sizes, so eyeball it before you order. Related: how to match hatch and hood gas struts by length, force, and ends.
Once you’ve got your numbers, here’s where to find quality replacements: Lift Supports. Don’t buy the cheapest ones on Amazon. The seals on bargain struts are garbage and you’ll be doing this job again in a year.
How to Swap Them Out
Difficulty: This is a one out of five. If you can change a light bulb, you can do this.
Time: 15 minutes for a pair, tops.
What you need: Flathead screwdriver, a helper or a sturdy prop, and that’s pretty much it.
First thing: do not take both struts off at once. The lid weighs a lot more than you think, and if that prop stick slips you’re in for a bad time. Replace them one side at a time.
Have your helper hold the hood or trunk open, or wedge a solid pole in there. A 2×4 cut to length works great. Do not use a hockey stick, a mop handle, or your head — yes, I’ve seen all three.
Look at the end of the strut where it snaps onto the ball stud. There’s a little metal spring clip — looks like a band wrapped around the socket. Slide a flathead under it and pry it outward just a little, maybe a quarter inch. You’re not removing the clip, just loosening it enough to pop the socket off the ball. Wiggle the strut end and pull it free. Do the same on the other end.
Now the new strut. Here’s a tip most people skip: install the fat end up, thin rod down. When the cylinder body is on top, the oil inside pools against the rod seal and keeps it lubricated. Rod-up installs dry the seals out faster. Every OEM mounts them body-up for a reason.
Push the new socket onto the ball stud. You’ll hear it snap. Give it a tug to make sure it’s seated. Make sure that retaining clip is pushed back down flat — if it’s sticking out, the strut can pop off while you’re driving and then you’ve got a hood flying up at sixty miles an hour. Ask me how I know.
Repeat on the other side. Always replace them in pairs. One new strut and one old one means uneven pressure, and the lid will twist when you open and close it. Over time that tweaks the hinges.
What Goes Wrong If You Guess Instead of Measure
I had a customer bring in his ’08 Camry trunk. He’d ordered lift supports online by just punching in his year and model. What showed up was the right extended length but about 30% less force than what Toyota spec’d. Trunk opened fine when it was warm out. First cold morning, he popped the trunk and it opened about eight inches and stopped. He had to crawl in through the back seat to get his jumper cables.
Another guy with a Tahoe ordered “rear lift supports” and got the ones for the glass hatch, not the whole liftgate. Those glass struts are rated for about forty pounds. A full liftgate weighs north of two hundred. He installed them, let go of the gate, and it dropped like a ton of bricks. Bent both mounting brackets.
Measure what’s on the car. Read the label. Match the force rating. It’s not complicated — you just have to actually do it.
Quick Vehicle Notes
Chevy Tahoe / Suburban (2007–2014): The rear glass and the liftgate use completely different struts. The glass struts are small, low-force. The liftgate struts are big, high-force, sometimes over 150 lbs each. Triple-check which position you’re replacing before you order.
Toyota Camry (2007–2011): These eat trunk struts. If yours has a factory spoiler, you need the higher-force version. Without it, the trunk will pop but won’t lift — you’ll have to heave it open by hand every time.
Ford Explorer (2011–2019): Hood struts fail early from engine bay heat. You’ll notice the hood getting heavier to lift over a few months, then one day it won’t stay up at all. Swap them before it surprises you in a gas station parking lot.
Here’s the bottom line. Lift supports are one of the cheapest, easiest fixes on any car. There’s no excuse for driving around propping your hood open with a broomstick or holding your trunk up with your shoulder while you dig for groceries. Measure your old struts, buy a decent pair, swap them on a Saturday morning, and never think about it again for another five or ten years.
And if you’ve been using a 2×4 to hold your hood open, do your skull a favor and go order the right parts today.
