Trunk Spring Adjustment
2000+ Bonneville

The intention of this tech article is to provide step-by-step instructions for adjusting the spring tension on the trunk of a 2000+ Bonneville.


Liability Statement:
Perform this task at your own risk! Neither the author nor anyone associated with this article accept ANY liability if you damage your car, hurt yourself, or otherwise screw something up. This is a guideline designed to help you perform the tasks described herein, therefore the risk is yours and so is the responsibility.

Application Note:
The following procedures were performed on a 2003 Bonneville SSEi. They should, however, be applicable to all vehicles with a similar spring arrangement.

Skill Level Required ~ 1-1.5
On a scale of 1 to 5 where
1 = What’s a wrench?
1.5 = I’ve seen a wrench before.
2 = Got me some tools!
2.5 = Got me some tools, and I know how ta use ‘em.
3 = Decent mechanic, but some things scare me.
3.5 = Good mechanic – ain’t skeert.
4 = Highly skilled in the mechanical arts.
4.5 = Mechanical wizard.
5 = Automotive god…don’t try this at home.

Tools Needed –
12” long 3/8” Drive socket extension (or something similar)

The first time I opened the trunk on my 2003 Bonneville, the deck lid opened up so hard & fast I thought the rear wheels came up off the ground. Aye Carumba! I couldn’t live with that, so I decided to do something about it. This turned out to be a very simple task. You can do this to take tension out of the trunk spring, or put more in (to a point). If your trunk pops open too hard, or doesn’t pop up at all, here’s how you rectify the problem. This assumes, of course, that your springs are both in good condition to begin with – this is an adjustment, not a replacement. Carry On!


1. Open the trunk, duh. Poke your head in there and look along the top of the trunk under the back window. See a couple of long rods that run from one side of the trunk to the other and form a shallow “X”? Them’s the springs what holds the deck lid up. Actually, they’re more like a torsion bar, but we’ll calls ‘em springs ‘cause it’s easier.

2. Follow either spring to it’s end and you will find, just outboard of the deck lid hinge, a bracket with three notches in it. The end of the spring should be hooked on one of these notches. Since there are two springs, logic would dictate that there are two of these brackets. Go look on the outboard side of the other deck lid hinge. Is there another bracket like this? Sweeeeet.

3. If your deck lid pops up too fast, you’ll want to take some tension out of the spring. Conversely, if you’d like your deck lid to come up a little faster/farther, you’ll want to put tension into the spring. Cool how that works, eh? To take tension out of the spring, you’ll want to move one, or both, of the springs into a lower notch. You should be able to figure out what to do to crank tension into the spring, you crazy rocket scientist, you.
4. You can move the spring to another notch using a hollow (or drilled) rod of some sort that will just slip over the end of the spring. I used a handy 3/8” drive socket extension…about 1 foot long or so. The ratchet end will slip over the spring nicely and it won’t bend. Not that there’s an excessive amount of tension in the springs, but you’re probably better off not using something like a stick of Bamboo. I found the easiest way to move the spring was to lie in the trunk on my back (first you’ll probably want to remove your spare PCMs, superchargers, crankshafts, whatever you store back there for emergencies), then slip the extension over the spring (make sure it bottoms out in the extension), and carefully lift & drop the spring to the next notch.

5. Hop outta there, close the trunk, then pop it open. Does it still open too hard for your liking? Then crawl back in and adjust the spring on the other side. Try the trunk again. Too strong still? If so, keep adjusting. You don’t have to have both springs in the same notch, and the tension rate appears to be different in each spring. What that means is that the deck lid will operate differently with the right spring in the second notch and the left spring in the third notch than vice versa (i.e. the left spring in the second notch and the right spring in the third). Experiment with different settings until the trunk opens how you like. Mine now opens slowly, waves at me for a few seconds then settles in the position in the picture.

6. Obviously there is a limit to the amount of adjustment you can do. If you have the springs in the lowest notch and the deck lid still acts like a Jack-In-The-Box, there’s not much you can do about that. Nothing simple, anyway. Again, the opposite is true – if you have the springs in the top notch and the deck lid just won’t come off the seal, you’re pretty much out of luck. The rest of us who have more cooperative trunks can adjust it to our liking and subsequently enjoy hours of playing with our trunks…trunk goes up, trunk goes down. Trunk goes up, trunk goes down, trunk goes up, trunk goes down…

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Resident Tightwad

Screw you, Photobucket.